diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2253082..bf1b9bc 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## [Unreleased]
 
 ### Added
+- **Pinyin abbreviation ranking**: drop dialect single-letter syllables (`m` / `n` / `ng` / `hm`) before abbrev so mixes like `wom` prefer 我们, matching rime-pinyin-simp; full pinyin also allows `zh` / `ch` / `sh` two-key abbrev (resource version `2.4.0`). / **拼音简拼排序**：在简拼前擦掉方言单字母音节（`m` / `n` / `ng` / `hm`），使 `wom` 一类混拼优先「我们」，对齐 rime-pinyin-simp；全拼同时支持 `zh` / `ch` / `sh` 两键简拼（资源版本 `2.4.0`）。
+- **Clear typing habits**: Settings → Text Input can reset learned Chinese Rime user dictionaries and English boosts without deleting the personal dictionary. / **清除打字习惯**：设置 → 文本输入可重置中文 Rime 用户词库与英文加分，不删除个性词库。
 - **Overlapping key presses**: the typing grid tracks multiple fingers, so the next key can go down before the previous lifts. Pending letters commit in press order (not release order); Shift can be held with one finger while another types. / **叠指连打**：打字网格跟踪多指，上一键未松开也可按下下一键。未提交的字母按按下顺序出字（而非抬手顺序）；一只手指按住 Shift 时另一只可打字。
 - **Period shortcut**: in English, a second Space shortly after a Space that follows a word becomes `. ` and arms sentence Shift, matching the system "." Shortcut. / **句号快捷**：英文下，在单词后的空格上短时间内再按一次空格会变成 `. ` 并点亮句首 Shift，对齐系统「句号快捷」。
 - **Return key labels**: Go / Search / Send / Done / Next / Join and the other `UIReturnKeyType` values show their system captions on the green action key instead of collapsing to Send or a return arrow. / **回车键文案**：前往 / 搜索 / 发送 / 完成 / 下一项 / 加入等 `UIReturnKeyType` 在绿色动作键上显示系统对应文案，不再一律变成「发送」或换行箭头。
@@ -26,6 +28,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - **Skill drag preview corners**: the lift preview clips to the card’s continuous rounded rect so square white corners no longer show. / **技能拖动圆角**：拖起预览按卡片连续圆角裁剪，去掉圆角外的直角白底。
 
 ### Changed
+- **Chinese user-dict flush**: leaving the typing surface finalizes librime so user-frequency ticks persist; secure fields insert Latin and skip Rime so passwords are not learned. / **中文用户词落盘**：离开打字表面时 finalize librime，使用频度得以保存；安全输入框改为直接插入拉丁字母、不进 Rime，避免把密码写入用户词库。
 - **Bundled Shortcut names**: Tasks and Events now install their signed in-app resources as `OSGExtractTodos` and `OSGExtractEvents`, matching `OSGSaveToNotes`; existing Chinese-named copies must be replaced from the Skills tab. / **内置捷径名称**：待办与日程改为安装 App 内签名资源 `OSGExtractTodos` 和 `OSGExtractEvents`，与 `OSGSaveToNotes` 保持一致；已有中文名称版本需从技能页重新安装。
 - **Navigation icons**: Skills uses a wand; Styles uses a dial. The phone dock and iPad sidebar (except Home) use outline when idle and fill when selected. Mac Styles / Settings follow the same pairing. iPad and Mac Home stay the house icon. / **导航图标**：技能改为魔杖，风格改为旋钮。手机 Dock 与 iPad 侧栏（除首页外）未选中描边、选中填充；Mac 的风格 / 设置同样切换。iPad / Mac 首页仍用房子图标。
 - **Phone dock size**: slightly smaller — 22 pt icons, 46 pt rows, 8 pt glass padding. / **手机 Dock 尺寸**：略缩小，图标 22 pt、行高 46 pt、玻璃内边距 8 pt。
diff --git a/OSGKeyboard/Services/RimeDeploymentController.swift b/OSGKeyboard/Services/RimeDeploymentController.swift
index 98fa0a0..c9c1dfd 100644
--- a/OSGKeyboard/Services/RimeDeploymentController.swift
+++ b/OSGKeyboard/Services/RimeDeploymentController.swift
@@ -90,4 +90,31 @@ final class RimeDeploymentController: ObservableObject {
             }
         }
     }
+
+    /// Wipes implicit typing habits under the same hostHeavy gate as deploy,
+    /// so the keyboard extension cannot keep LevelDB open while files vanish.
+    func clearTypingHabits() {
+        guard activeTask == nil else { return }
+
+        OSGDiag.log("typing.habits.clear begin \(OSGDiag.memoryTag())", category: "flow")
+        status = .deploying
+        activeTask = Task { @MainActor in
+            defer { activeTask = nil }
+            FlowSessionBridge.setHostHeavy(true)
+            do {
+                try await TypingHabitStore.clearAll()
+                FlowSessionBridge.setHostHeavy(false)
+                AppGroupConfigDarwin.postConfigChanged()
+                status = RimeResourceInstaller.isReady ? .ready : .idle
+                OSGDiag.log("typing.habits.clear done \(OSGDiag.memoryTag())", category: "flow")
+            } catch {
+                FlowSessionBridge.setHostHeavy(false)
+                status = .failed(error.localizedDescription)
+                OSGDiag.log(
+                    "typing.habits.clear failed error=\(error.localizedDescription)",
+                    category: "flow"
+                )
+            }
+        }
+    }
 }
diff --git a/OSGKeyboard/Views/TypingInputSettingsView.swift b/OSGKeyboard/Views/TypingInputSettingsView.swift
index cb7864b..f7a7698 100644
--- a/OSGKeyboard/Views/TypingInputSettingsView.swift
+++ b/OSGKeyboard/Views/TypingInputSettingsView.swift
@@ -12,6 +12,7 @@ struct TypingInputSettingsView: View {
     @ObservedObject private var config = ProviderConfig.shared
     @ObservedObject private var configuration = TypingInputConfiguration.shared
     @ObservedObject private var deployment = RimeDeploymentController.shared
+    @State private var showClearHabitsConfirmation = false
 
     private var isDeploying: Bool { deployment.isDeploying }
 
@@ -69,11 +70,36 @@ struct TypingInputSettingsView: View {
                 }
                 .disabled(isDeploying)
             }
+
+            Section {
+                Button(AppL10n.string("settings.typingInput.habits.clear", language: config.uiLanguage)) {
+                    showClearHabitsConfirmation = true
+                }
+                .disabled(isDeploying)
+                .foregroundStyle(palette.danger)
+            } footer: {
+                Text(AppL10n.string("settings.typingInput.habits.footer", language: config.uiLanguage))
+            }
         }
         .scrollContentBackground(.hidden)
         .background(palette.background)
         .navigationTitle(AppL10n.string("settings.typingInput.title", language: config.uiLanguage))
         .navigationBarTitleDisplayMode(.inline)
+        .confirmationDialog(
+            AppL10n.string("settings.typingInput.habits.clear.title", language: config.uiLanguage),
+            isPresented: $showClearHabitsConfirmation,
+            titleVisibility: .visible
+        ) {
+            Button(
+                AppL10n.string("settings.typingInput.habits.clear.confirm", language: config.uiLanguage),
+                role: .destructive
+            ) {
+                deployment.clearTypingHabits()
+            }
+            Button(AppL10n.string("common.cancel", language: config.uiLanguage), role: .cancel) {}
+        } message: {
+            Text(AppL10n.string("settings.typingInput.habits.clear.message", language: config.uiLanguage))
+        }
     }
 
     private var hasDeploymentError: Bool {
diff --git a/OSGKeyboard/en.lproj/Localizable.strings b/OSGKeyboard/en.lproj/Localizable.strings
index d684e4b..f4810ca 100644
--- a/OSGKeyboard/en.lproj/Localizable.strings
+++ b/OSGKeyboard/en.lproj/Localizable.strings
@@ -238,6 +238,11 @@
 "settings.typingInput.resources.ready" = "Ready";
 "settings.typingInput.resources.pending" = "Not initialized";
 "settings.typingInput.resources.redeploy" = "Redeploy Input Resources";
+"settings.typingInput.habits.clear" = "Clear Typing Habits";
+"settings.typingInput.habits.clear.title" = "Clear Typing Habits?";
+"settings.typingInput.habits.clear.confirm" = "Clear";
+"settings.typingInput.habits.clear.message" = "Resets learned word order for Chinese and English. Personal dictionary entries are kept.";
+"settings.typingInput.habits.footer" = "Learned frequency only. Words you added to the personal dictionary stay.";
 "settings.speechRecognition.title" = "Speech Recognition";
 "settings.textPolish.title" = "Text Polish";
 "settings.preferences.title" = "Preferences";
diff --git a/OSGKeyboard/zh-Hans.lproj/Localizable.strings b/OSGKeyboard/zh-Hans.lproj/Localizable.strings
index 122ed85..d443994 100644
--- a/OSGKeyboard/zh-Hans.lproj/Localizable.strings
+++ b/OSGKeyboard/zh-Hans.lproj/Localizable.strings
@@ -238,6 +238,11 @@
 "settings.typingInput.resources.ready" = "已就绪";
 "settings.typingInput.resources.pending" = "待初始化";
 "settings.typingInput.resources.redeploy" = "重新部署输入法资源";
+"settings.typingInput.habits.clear" = "清除打字习惯";
+"settings.typingInput.habits.clear.title" = "清除打字习惯？";
+"settings.typingInput.habits.clear.confirm" = "清除";
+"settings.typingInput.habits.clear.message" = "将重置中文和英文的学习词序。个性词库中的词条会保留。";
+"settings.typingInput.habits.footer" = "只清除使用频度。你手动加入个性词库的词不会受影响。";
 "settings.speechRecognition.title" = "语音识别";
 "settings.textPolish.title" = "文本润色";
 "settings.preferences.title" = "偏好设置";
diff --git a/OSGKeyboardExtTests/EnglishTypingTests.swift b/OSGKeyboardExtTests/EnglishTypingTests.swift
index fbb9c2c..602c746 100644
--- a/OSGKeyboardExtTests/EnglishTypingTests.swift
+++ b/OSGKeyboardExtTests/EnglishTypingTests.swift
@@ -370,6 +370,19 @@ final class EnglishTypingTests: XCTestCase {
         XCTAssertFalse(PeriodShortcut.shouldArm(afterSpaceFollowing: "hello "))
     }
 
+    func testLearningStoreClearRemovesBoosts() {
+        let suiteName = "EnglishLearningStore.clear.\(UUID().uuidString)"
+        let defaults = UserDefaults(suiteName: suiteName)!
+        defer { defaults.removePersistentDomain(forName: suiteName) }
+
+        let store = EnglishLearningStore(defaults: defaults)
+        store.recordAcceptance(of: "hello")
+        XCTAssertGreaterThan(store.boost(for: "hello"), 0)
+        store.clear()
+        XCTAssertEqual(store.boost(for: "hello"), 0)
+        XCTAssertTrue(store.snapshot().isEmpty)
+    }
+
     @MainActor
     private func apply(_ typing: TypingSessionController, _ output: TypingOutput) {
         typing.syncAutocapitalization(
diff --git a/OSGKeyboardExtTests/KeyboardSurfaceStateTests.swift b/OSGKeyboardExtTests/KeyboardSurfaceStateTests.swift
index c91ae52..e961e98 100644
--- a/OSGKeyboardExtTests/KeyboardSurfaceStateTests.swift
+++ b/OSGKeyboardExtTests/KeyboardSurfaceStateTests.swift
@@ -456,6 +456,24 @@ final class KeyboardSurfaceStateTests: XCTestCase {
         XCTAssertEqual(engine.lastProcessedCharacter, "n")
         XCTAssertEqual(typing.composition.preedit, "n")
     }
+
+    func testSecureFieldInsertsLatinWithoutRime() {
+        let engine = TrackingStubRimeEngine()
+        let typing = TypingSessionController(engine: { engine })
+
+        _ = typing.handleKey("n")
+        XCTAssertEqual(engine.processCharacterCallCount, 1)
+
+        typing.suggestionsEnabled = false
+        XCTAssertTrue(typing.composition.preedit.isEmpty)
+        XCTAssertEqual(engine.clearCompositionCallCount, 1)
+
+        XCTAssertEqual(typing.handleKey("a"), .insert("a"))
+        XCTAssertEqual(engine.processCharacterCallCount, 1)
+        XCTAssertEqual(typing.handleSpace(), .insert(" "))
+        XCTAssertEqual(engine.processSpaceCallCount, 0)
+        XCTAssertEqual(typing.selectCandidate(at: 0), .none)
+    }
 }
 
 /// Stub that records `processCharacter` calls for Chinese Shift bypass tests.
@@ -465,6 +483,8 @@ private final class TrackingStubRimeEngine: RimeEngineBridging {
     var isReady: Bool = true
     var schema: TypingInputSchema = .fullPinyin
     private(set) var processCharacterCallCount = 0
+    private(set) var processSpaceCallCount = 0
+    private(set) var clearCompositionCallCount = 0
     private(set) var lastProcessedCharacter: Character?
 
     func prepare() async throws {}
@@ -496,6 +516,7 @@ private final class TrackingStubRimeEngine: RimeEngineBridging {
     }
 
     func processSpace() -> String? {
+        processSpaceCallCount += 1
         composition = .empty
         return " "
     }
@@ -517,6 +538,7 @@ private final class TrackingStubRimeEngine: RimeEngineBridging {
     }
 
     func clearComposition() {
+        clearCompositionCallCount += 1
         composition = .empty
     }
 }
diff --git a/OSGKeyboardExtTests/LibrimeIntegrationTests.swift b/OSGKeyboardExtTests/LibrimeIntegrationTests.swift
index 0510e87..0adc73c 100644
--- a/OSGKeyboardExtTests/LibrimeIntegrationTests.swift
+++ b/OSGKeyboardExtTests/LibrimeIntegrationTests.swift
@@ -1,6 +1,7 @@
 // LibrimeIntegrationTests.swift
 // OSGKeyboard · Ext unit tests
 
+import Darwin
 import XCTest
 @testable import OSGKeyboardShared
 
@@ -264,4 +265,365 @@ final class LibrimeIntegrationTests: XCTestCase {
         )
         bridge.finalizeRuntime()
     }
+
+    func testAbbreviatedPinyinPrefersHighFrequencyPhrases() throws {
+        let env = try deployedRimeEnvironment()
+        defer { try? env.fileManager.removeItem(at: env.root) }
+
+        let bridge = OSGRimeBridge(
+            sharedDataDirectory: env.shared.path,
+            userDataDirectory: env.user.path,
+            distributionVersion: "tests-abbrev"
+        )
+        try bridge.start()
+        defer { bridge.finalizeRuntime() }
+        XCTAssertTrue(bridge.selectSchema(TypingInputSchema.fullPinyin.rawValue))
+
+        let cases: [(String, String)] = [
+            ("wom", "我们"),
+            ("wm", "我们"),
+            ("women", "我们"),
+            ("bn", "不能"),
+            ("nh", "你好"),
+            ("nihao", "你好")
+        ]
+        for (keys, expected) in cases {
+            type(keys, on: bridge)
+            let snapshot = bridge.snapshot(withCandidateLimit: 40)
+            let texts = snapshot.candidates.map(\.text)
+            XCTAssertEqual(
+                texts.first,
+                expected,
+                "\(keys) top-1 \(texts.prefix(12))"
+            )
+            XCTAssertNotEqual(texts.first, "我呒")
+            XCTAssertFalse(texts.prefix(3).contains("我呒"))
+        }
+
+        type("zhangwei", on: bridge)
+        let zhangwei = bridge.snapshot(withCandidateLimit: 40)
+        XCTAssertTrue(
+            zhangwei.candidates.contains(where: { $0.text == "张伟" }),
+            "zhangwei: \(zhangwei.candidates.map(\.text).prefix(20))"
+        )
+
+        type("zhg", on: bridge)
+        let zhg = bridge.snapshot(withCandidateLimit: 40)
+        XCTAssertTrue(
+            zhg.candidates.contains(where: { $0.text == "中国" }),
+            "zhg should reach 中国 via zh abbrev: \(zhg.candidates.map(\.text).prefix(20))"
+        )
+    }
+
+    func testUserDictionaryLearnsSelectedPhraseAcrossFinalize() throws {
+        let env = try deployedRimeEnvironment()
+        defer { try? env.fileManager.removeItem(at: env.root) }
+
+        let bridge = OSGRimeBridge(
+            sharedDataDirectory: env.shared.path,
+            userDataDirectory: env.user.path,
+            distributionVersion: "tests-learn"
+        )
+        try bridge.start()
+        defer { bridge.finalizeRuntime() }
+        XCTAssertTrue(bridge.selectSchema(TypingInputSchema.fullPinyin.rawValue))
+
+        type("zhangwei", on: bridge)
+        let before = bridge.snapshot(withCandidateLimit: 80)
+        let startIndex = try XCTUnwrap(
+            before.candidates.firstIndex(where: { $0.text == "张伟" }),
+            "missing 张伟: \(before.candidates.map(\.text).prefix(20))"
+        )
+        for _ in 0..<8 {
+            type("zhangwei", on: bridge)
+            let snapshot = bridge.snapshot(withCandidateLimit: 80)
+            let current = try XCTUnwrap(snapshot.candidates.first(where: { $0.text == "张伟" }))
+            XCTAssertTrue(bridge.selectCandidate(at: current.index))
+            _ = bridge.snapshot(withCandidateLimit: 8)
+        }
+        bridge.finalizeRuntime()
+
+        let reopened = OSGRimeBridge(
+            sharedDataDirectory: env.shared.path,
+            userDataDirectory: env.user.path,
+            distributionVersion: "tests-learn"
+        )
+        try reopened.start()
+        defer { reopened.finalizeRuntime() }
+        XCTAssertTrue(reopened.selectSchema(TypingInputSchema.fullPinyin.rawValue))
+        type("zhangwei", on: reopened)
+        let after = reopened.snapshot(withCandidateLimit: 80)
+        let learnedIndex = try XCTUnwrap(
+            after.candidates.firstIndex(where: { $0.text == "张伟" })
+        )
+        XCTAssertLessThanOrEqual(learnedIndex, startIndex)
+        reopened.finalizeRuntime()
+
+        try RimeResourceInstaller.removeUserDictionaries(in: env.user)
+        let names = try env.fileManager.contentsOfDirectory(atPath: env.user.path)
+        XCTAssertFalse(names.contains { $0.lowercased().contains("userdb") })
+        XCTAssertTrue(
+            env.fileManager.fileExists(atPath: env.user.appendingPathComponent("build").path)
+        )
+    }
+
+    func testAssembledPhraseBecomesUserWord() throws {
+        let env = try deployedRimeEnvironment()
+        defer { try? env.fileManager.removeItem(at: env.root) }
+
+        let bridge = OSGRimeBridge(
+            sharedDataDirectory: env.shared.path,
+            userDataDirectory: env.user.path,
+            distributionVersion: "tests-encode"
+        )
+        try bridge.start()
+        defer { bridge.finalizeRuntime() }
+        XCTAssertTrue(bridge.selectSchema(TypingInputSchema.fullPinyin.rawValue))
+
+        type("chu", on: bridge)
+        let chuSnap = bridge.snapshot(withCandidateLimit: 80)
+        let chu = try XCTUnwrap(
+            chuSnap.candidates.first(where: { $0.text == "褚" }),
+            "missing 褚: \(chuSnap.candidates.map(\.text).prefix(20))"
+        )
+        XCTAssertTrue(bridge.selectCandidate(at: chu.index))
+        _ = bridge.snapshot(withCandidateLimit: 8)
+
+        type("han", on: bridge)
+        let hanSnap = bridge.snapshot(withCandidateLimit: 80)
+        let han = try XCTUnwrap(
+            hanSnap.candidates.first(where: { $0.text == "寒" }),
+            "missing 寒: \(hanSnap.candidates.map(\.text).prefix(20))"
+        )
+        XCTAssertTrue(bridge.selectCandidate(at: han.index))
+        _ = bridge.snapshot(withCandidateLimit: 8)
+
+        type("chuhan", on: bridge)
+        let learned = bridge.snapshot(withCandidateLimit: 80)
+        let assembled = learned.candidates.contains(where: { $0.text == "褚寒" })
+        if !assembled {
+            throw XCTSkip(
+                "script_translator did not persist 褚寒 after 褚+寒 commits: "
+                    + "\(learned.candidates.map(\.text).prefix(20)). "
+                    + "Auto-phrasing stays a follow-up, not a Swift overlay in this slice."
+            )
+        }
+    }
+
+    /// Host 2.4.0 部署 + 扩展 prepare/teardown 循环。phys_footprint 更接近
+    /// 实体机 jetsam 口径；绝对值含 XCTest 进程，只看相对增量。
+    func testHostDeployAndTypingCyclesKeepMemoryStable() throws {
+        let staged = try stagedRimeEnvironment()
+        defer { try? staged.fileManager.removeItem(at: staged.root) }
+
+        let beforeDeploy = MemoryProbe.capture()
+        let deployer = OSGRimeBridge(
+            sharedDataDirectory: staged.shared.path,
+            userDataDirectory: staged.user.path,
+            distributionVersion: "tests-memory-deploy"
+        )
+        try deployer.deploy(withFullCheck: true)
+        let afterDeploy = MemoryProbe.capture()
+        deployer.finalizeRuntime()
+        let afterHostFinalize = MemoryProbe.capture()
+
+        let deployFootprintGrowth = afterDeploy.physFootprintMB - beforeDeploy.physFootprintMB
+        let deployRSSGrowth = afterDeploy.rssMB - beforeDeploy.rssMB
+        XCTContext.runActivity(named: "host deploy footprint") { _ in
+            NSLog(
+                "[OSGDiag/rime-mem] deploy rss=%.1f→%.1fMB deltaRSS=%.1fMB foot=%.1f→%.1fMB deltaFoot=%.1fMB finalize rss=%.1fMB foot=%.1fMB",
+                beforeDeploy.rssMB,
+                afterDeploy.rssMB,
+                deployRSSGrowth,
+                beforeDeploy.physFootprintMB,
+                afterDeploy.physFootprintMB,
+                deployFootprintGrowth,
+                afterHostFinalize.rssMB,
+                afterHostFinalize.physFootprintMB
+            )
+        }
+        // Simulator phys_footprint is compressed and often stays flat; RSS
+        // still catches anonymous growth. Device jetsam follows footprint.
+        XCTAssertLessThan(
+            deployFootprintGrowth,
+            HostMemoryBudget.deferHeavyWorkAboveMB,
+            "host deploy footprint grew \(String(format: "%.1f", deployFootprintGrowth)) MB"
+        )
+        XCTAssertLessThan(
+            deployFootprintGrowth,
+            80,
+            "host deploy footprint grew \(String(format: "%.1f", deployFootprintGrowth)) MB (budget estimate is 24 MB)"
+        )
+
+        var peakTyping = afterHostFinalize
+        var lastIdle = afterHostFinalize
+        let cycleCount = 20
+        for cycle in 1...cycleCount {
+            try autoreleasepool {
+                let bridge = OSGRimeBridge(
+                    sharedDataDirectory: staged.shared.path,
+                    userDataDirectory: staged.user.path,
+                    distributionVersion: "tests-memory-session"
+                )
+                try bridge.start()
+                XCTAssertTrue(bridge.selectSchema(TypingInputSchema.fullPinyin.rawValue))
+                // Production LibrimeEngine copies 160 candidates per keystroke.
+                for keys in ["nihao", "wom", "zhangwei", "zhongg"] {
+                    type(keys, on: bridge)
+                    _ = bridge.snapshot(withCandidateLimit: 160)
+                }
+                let during = MemoryProbe.capture()
+                if during.physFootprintMB > peakTyping.physFootprintMB {
+                    peakTyping = during
+                }
+                bridge.finalizeRuntime()
+            }
+            lastIdle = MemoryProbe.capture()
+            NSLog(
+                "[OSGDiag/rime-mem] cycle=%d idleFoot=%.1fMB peakFoot=%.1fMB rss=%.1fMB",
+                cycle,
+                lastIdle.physFootprintMB,
+                peakTyping.physFootprintMB,
+                lastIdle.rssMB
+            )
+        }
+
+        let idleFootprintGrowth = lastIdle.physFootprintMB - afterHostFinalize.physFootprintMB
+        let idleRSSGrowth = lastIdle.rssMB - afterHostFinalize.rssMB
+        let sessionPeak = peakTyping.physFootprintMB - afterHostFinalize.physFootprintMB
+        XCTAssertLessThan(
+            idleFootprintGrowth,
+            16,
+            "\(cycleCount) prepare/finalize cycles leaked \(String(format: "%.1f", idleFootprintGrowth)) MB footprint"
+        )
+        // Debug malloc is noisy; a real initialize/finalize leak would climb each cycle.
+        XCTAssertLessThan(
+            idleRSSGrowth,
+            24,
+            "\(cycleCount) prepare/finalize cycles leaked \(String(format: "%.1f", idleRSSGrowth)) MB RSS"
+        )
+        XCTAssertLessThan(
+            sessionPeak,
+            40,
+            "typing session peak added \(String(format: "%.1f", sessionPeak)) MB above post-deploy idle"
+        )
+
+        try RimeResourceInstaller.removeUserDictionaries(in: staged.user)
+        let afterClear = MemoryProbe.capture()
+        XCTAssertLessThan(
+            afterClear.physFootprintMB - lastIdle.physFootprintMB,
+            8,
+            "clearing userdb while runtime is down should be a file-only wipe"
+        )
+    }
+
+    func testRemoveUserDictionariesKeepsBuildDirectory() throws {
+        let fileManager = FileManager.default
+        let user = fileManager.temporaryDirectory
+            .appendingPathComponent("OSGUserDB-\(UUID().uuidString)", isDirectory: true)
+        defer { try? fileManager.removeItem(at: user) }
+        try fileManager.createDirectory(at: user.appendingPathComponent("build"), withIntermediateDirectories: true)
+        try fileManager.createDirectory(
+            at: user.appendingPathComponent("osg_pinyin.userdb"),
+            withIntermediateDirectories: true
+        )
+        try "keep\n".write(
+            to: user.appendingPathComponent("user.yaml"),
+            atomically: true,
+            encoding: .utf8
+        )
+
+        try RimeResourceInstaller.removeUserDictionaries(in: user)
+        XCTAssertTrue(fileManager.fileExists(atPath: user.appendingPathComponent("build").path))
+        XCTAssertTrue(fileManager.fileExists(atPath: user.appendingPathComponent("user.yaml").path))
+        XCTAssertFalse(
+            fileManager.fileExists(atPath: user.appendingPathComponent("osg_pinyin.userdb").path)
+        )
+    }
+
+    private func stagedRimeEnvironment() throws -> (
+        root: URL,
+        shared: URL,
+        user: URL,
+        fileManager: FileManager
+    ) {
+        let fileManager = FileManager.default
+        let root = fileManager.temporaryDirectory
+            .appendingPathComponent("OSGRimeTests-\(UUID().uuidString)", isDirectory: true)
+        let shared = root.appendingPathComponent("SharedSupport", isDirectory: true)
+        let user = root.appendingPathComponent("UserData", isDirectory: true)
+        try fileManager.createDirectory(at: shared, withIntermediateDirectories: true)
+        try fileManager.createDirectory(at: user, withIntermediateDirectories: true)
+
+        let bundle = Bundle(for: LibrimeIntegrationTests.self)
+        let dictionary = try XCTUnwrap(
+            bundle.url(forResource: "osg_pinyin.dict", withExtension: "yaml")
+        )
+        try fileManager.copyItem(
+            at: dictionary,
+            to: shared.appendingPathComponent("osg_pinyin.dict.yaml")
+        )
+        try RimeSchemaGenerator.defaultConfiguration().write(
+            to: shared.appendingPathComponent("default.yaml"),
+            atomically: true,
+            encoding: .utf8
+        )
+        for schema in TypingInputSchema.allCases {
+            try RimeSchemaGenerator.schema(for: schema, fuzzyPairs: []).write(
+                to: shared.appendingPathComponent("\(schema.rawValue).schema.yaml"),
+                atomically: true,
+                encoding: .utf8
+            )
+        }
+        return (root, shared, user, fileManager)
+    }
+
+    private func deployedRimeEnvironment() throws -> (
+        root: URL,
+        shared: URL,
+        user: URL,
+        fileManager: FileManager
+    ) {
+        let staged = try stagedRimeEnvironment()
+        let deployer = OSGRimeBridge(
+            sharedDataDirectory: staged.shared.path,
+            userDataDirectory: staged.user.path,
+            distributionVersion: "tests"
+        )
+        try deployer.deploy(withFullCheck: true)
+        deployer.finalizeRuntime()
+        return staged
+    }
+
+    private func type(_ keys: String, on bridge: OSGRimeBridge) {
+        bridge.clearComposition()
+        for scalar in keys.utf8 {
+            XCTAssertTrue(bridge.processKeyCode(Int32(scalar), modifiers: 0), keys)
+        }
+    }
+}
+
+/// RSS plus phys_footprint. Jetsam on device tracks footprint more closely
+/// than `task_basic_info.resident_size`.
+private struct MemoryProbe {
+    let rssMB: Double
+    let physFootprintMB: Double
+
+    static func capture() -> MemoryProbe {
+        MemoryProbe(rssMB: OSGDiag.memoryMB(), physFootprintMB: physFootprintMB())
+    }
+
+    private static func physFootprintMB() -> Double {
+        var info = task_vm_info_data_t()
+        var count = mach_msg_type_number_t(
+            MemoryLayout<task_vm_info_data_t>.size / MemoryLayout<natural_t>.size
+        )
+        let kr = withUnsafeMutablePointer(to: &info) { ptr in
+            ptr.withMemoryRebound(to: integer_t.self, capacity: Int(count)) { rebound in
+                task_info(mach_task_self_, task_flavor_t(TASK_VM_INFO), rebound, &count)
+            }
+        }
+        guard kr == KERN_SUCCESS else { return -1 }
+        return Double(info.phys_footprint) / 1_048_576.0
+    }
 }
diff --git a/OSGKeyboardExtTests/RimeSchemaGeneratorTests.swift b/OSGKeyboardExtTests/RimeSchemaGeneratorTests.swift
index 07ac8b3..4bf56a3 100644
--- a/OSGKeyboardExtTests/RimeSchemaGeneratorTests.swift
+++ b/OSGKeyboardExtTests/RimeSchemaGeneratorTests.swift
@@ -41,6 +41,37 @@ final class RimeSchemaGeneratorTests: XCTestCase {
         XCTAssertLessThan(fuzzy.lowerBound, transform.lowerBound)
     }
 
+    func testDialectErasePrecedesFuzzyAndAbbrev() throws {
+        let yaml = RimeSchemaGenerator.schema(for: .fullPinyin, fuzzyPairs: [.nL])
+        let eraseN = try XCTUnwrap(yaml.range(of: "erase/^n$/"))
+        let fuzzy = try XCTUnwrap(yaml.range(of: "derive/^n/l/"))
+        let abbrev = try XCTUnwrap(yaml.range(of: "abbrev/^([a-z]).+$/$1/"))
+        XCTAssertLessThan(eraseN.lowerBound, fuzzy.lowerBound)
+        XCTAssertLessThan(fuzzy.lowerBound, abbrev.lowerBound)
+    }
+
+    func testAllSchemasEraseDialectSyllables() {
+        for schema in TypingInputSchema.allCases {
+            let yaml = RimeSchemaGenerator.schema(for: schema, fuzzyPairs: [])
+            XCTAssertTrue(yaml.contains("erase/^hm$/"), schema.rawValue)
+            XCTAssertTrue(yaml.contains("erase/^m$/"), schema.rawValue)
+            XCTAssertTrue(yaml.contains("erase/^n$/"), schema.rawValue)
+            XCTAssertTrue(yaml.contains("erase/^ng$/"), schema.rawValue)
+        }
+    }
+
+    func testZhAbbrevIsFullPinyinOnly() {
+        let full = RimeSchemaGenerator.schema(for: .fullPinyin, fuzzyPairs: [])
+        XCTAssertTrue(full.contains("abbrev/^([zcs]h).+$/$1/"))
+        for schema in [TypingInputSchema.microsoftDoublePinyin, .sogouDoublePinyin] {
+            let yaml = RimeSchemaGenerator.schema(for: schema, fuzzyPairs: [])
+            XCTAssertFalse(
+                yaml.contains("abbrev/^([zcs]h).+$/$1/"),
+                schema.rawValue
+            )
+        }
+    }
+
     @MainActor
     func testTypingConfigurationDefaultsToFullPinyinWithoutFuzzyPairs() {
         let suiteName = "TypingInputConfigurationTests.\(UUID().uuidString)"
diff --git a/OSGKeyboardShared/Typing/EnglishLearningStore.swift b/OSGKeyboardShared/Typing/EnglishLearningStore.swift
index e15451f..1ef2899 100644
--- a/OSGKeyboardShared/Typing/EnglishLearningStore.swift
+++ b/OSGKeyboardShared/Typing/EnglishLearningStore.swift
@@ -35,6 +35,10 @@ public final class EnglishLearningStore: @unchecked Sendable {
         (defaults.dictionary(forKey: Self.defaultsKey) as? [String: Int]) ?? [:]
     }
 
+    public func clear() {
+        defaults.removeObject(forKey: Self.defaultsKey)
+    }
+
     private func mutate(word: String, delta: Int) {
         let key = word.lowercased()
         guard !key.isEmpty else { return }
diff --git a/OSGKeyboardShared/Typing/LibrimeEngine.swift b/OSGKeyboardShared/Typing/LibrimeEngine.swift
index fe93022..6b68737 100644
--- a/OSGKeyboardShared/Typing/LibrimeEngine.swift
+++ b/OSGKeyboardShared/Typing/LibrimeEngine.swift
@@ -58,7 +58,8 @@ public final class LibrimeEngine: RimeEngineBridging {
 
     public func teardown() {
         bridge?.clearComposition()
-        bridge?.stopSession()
+        // Session destroy alone does not flush LevelDB user dictionaries.
+        bridge?.finalizeRuntime()
         bridge = nil
         composition = .empty
         isReady = false
diff --git a/OSGKeyboardShared/Typing/RimeResourceInstaller.swift b/OSGKeyboardShared/Typing/RimeResourceInstaller.swift
index 20b7e6b..cc62feb 100644
--- a/OSGKeyboardShared/Typing/RimeResourceInstaller.swift
+++ b/OSGKeyboardShared/Typing/RimeResourceInstaller.swift
@@ -72,7 +72,7 @@ public struct RimeResourcePaths: Sendable {
 public actor RimeResourceInstaller {
     public static let shared = RimeResourceInstaller()
     /// Bump when SharedSupport layout / schema / import_tables contract changes.
-    public static let resourceVersion = "2.3.0"
+    public static let resourceVersion = "2.4.0"
 
     public init() {}
 
@@ -231,6 +231,28 @@ public actor RimeResourceInstaller {
         // deployments and is intentionally not needed here.
         bridge.finalizeRuntime()
     }
+
+    /// Deletes librime user dictionaries under `UserData`, keeping `build/`
+    /// so `isReady` stays true. Host-only: the keyboard must not race LevelDB.
+    public func clearUserDictionary() throws {
+        guard Self.canDeployInCurrentProcess else {
+            throw RimeResourceError.hostAppRequired
+        }
+        let paths = try RimeResourcePaths.resolve()
+        try Self.removeUserDictionaries(in: paths.userData)
+    }
+
+    /// Testable file-level wipe. Matches LevelDB folders like `osg_pinyin.userdb`.
+    nonisolated public static func removeUserDictionaries(
+        in userData: URL,
+        fileManager: FileManager = .default
+    ) throws {
+        guard fileManager.fileExists(atPath: userData.path) else { return }
+        let names = try fileManager.contentsOfDirectory(atPath: userData.path)
+        for name in names where name.lowercased().contains("userdb") {
+            try fileManager.removeItem(at: userData.appendingPathComponent(name))
+        }
+    }
 }
 
 extension RimeResourceInstaller {
diff --git a/OSGKeyboardShared/Typing/RimeSchemaGenerator.swift b/OSGKeyboardShared/Typing/RimeSchemaGenerator.swift
index a3ce2c1..7d742dd 100644
--- a/OSGKeyboardShared/Typing/RimeSchemaGenerator.swift
+++ b/OSGKeyboardShared/Typing/RimeSchemaGenerator.swift
@@ -43,7 +43,9 @@ public enum RimeSchemaGenerator {
         let alphabet = inputSchema == .fullPinyin
             ? "zyxwvutsrqponmlkjihgfedcba"
             : "zyxwvutsrqponmlkjihgfedcba;"
-        let algebra = fuzzyRules(fuzzyPairs) + algebraRules(for: inputSchema)
+        // Dialect single-letter syllables must be erased before fuzzy/abbrev
+        // so `n/l` cannot revive 嗯 as `l`, and `wom` cannot exact-match 我呒.
+        let algebra = dialectEraseRules + fuzzyRules(fuzzyPairs) + algebraRules(for: inputSchema)
         let algebraYAML = algebra.map { "    - '\($0)'" }.joined(separator: "\n")
 
         return """
@@ -112,6 +114,16 @@ public enum RimeSchemaGenerator {
         """
     }
 
+    /// Drop Wu/dialect exact spellings (`呒 m`, `嗯 n/ng`, `噷 hm`) before
+    /// first-letter abbrev, matching rime-pinyin-simp. Keep the dictionary
+    /// rows; 嗯 remains reachable as `en`, 呒 as `mu`.
+    public static let dialectEraseRules: [String] = [
+        "erase/^hm$/",
+        "erase/^m$/",
+        "erase/^n$/",
+        "erase/^ng$/"
+    ]
+
     /// Rules run against full-pinyin dictionary codes before double-pinyin
     /// transforms, so fuzzy pairs work consistently in all three schemas.
     public static func fuzzyRules(_ enabled: Set<PinyinFuzzyPair>) -> [String] {
@@ -144,7 +156,9 @@ public enum RimeSchemaGenerator {
         case .fullPinyin:
             return [
                 "derive/^([jqxy])u$/$1v/",
-                "abbrev/^([a-z]).+$/$1/"
+                "abbrev/^([a-z]).+$/$1/",
+                // Two-letter initials; do not add this to double pinyin.
+                "abbrev/^([zcs]h).+$/$1/"
             ]
 
         case .microsoftDoublePinyin, .sogouDoublePinyin:
diff --git a/OSGKeyboardShared/Typing/TypingHabitStore.swift b/OSGKeyboardShared/Typing/TypingHabitStore.swift
new file mode 100644
index 0000000..8e39bf8
--- /dev/null
+++ b/OSGKeyboardShared/Typing/TypingHabitStore.swift
@@ -0,0 +1,18 @@
+// TypingHabitStore.swift
+// OSGKeyboard · Shared
+//
+// Cross-language "forget" for implicit typing habits. Ranking stays
+// language-specific (EnglishLearningStore vs librime userdb).
+
+import Foundation
+
+public enum TypingHabitStore {
+    /// Clears English boosts and Chinese Rime user dictionaries.
+    /// Does not touch PersonalDictionary / osg_personal.
+    public static func clearAll(
+        englishStore: EnglishLearningStore = EnglishLearningStore()
+    ) async throws {
+        englishStore.clear()
+        try await RimeResourceInstaller.shared.clearUserDictionary()
+    }
+}
diff --git a/OSGKeyboardShared/Typing/TypingSessionController.swift b/OSGKeyboardShared/Typing/TypingSessionController.swift
index 2156d2c..147ea35 100644
--- a/OSGKeyboardShared/Typing/TypingSessionController.swift
+++ b/OSGKeyboardShared/Typing/TypingSessionController.swift
@@ -26,7 +26,13 @@ public final class TypingSessionController: ObservableObject {
     @Published public private(set) var lastErrorNeedsHostDeployment: Bool = false
 
     /// When true, English suggestions / autocorrect stay off (secure fields).
-    @Published public var suggestionsEnabled: Bool = true
+    /// Chinese composition is also skipped so passwords never enter Rime userdb.
+    @Published public var suggestionsEnabled: Bool = true {
+        didSet {
+            guard oldValue, !suggestionsEnabled else { return }
+            abandonChineseComposition()
+        }
+    }
 
     /// Chevron appears only for Chinese composition with at least two candidates.
     public var canExpandCandidatePanel: Bool {
@@ -306,6 +312,12 @@ public final class TypingSessionController: ObservableObject {
             return handleEnglishCharacter(ch)
         }
 
+        if !suggestionsEnabled {
+            clearOneShotShiftIfNeeded()
+            abandonChineseComposition()
+            return .insert(String(ch))
+        }
+
         // Chinese + Shift: insert Latin directly (iOS-style mix-in), leave Rime
         // composition untouched. Rime's alphabet is lowercase-only, so uppercase
         // keycodes would otherwise be rejected with no output.
@@ -327,6 +339,10 @@ public final class TypingSessionController: ObservableObject {
             return handleEnglishSpace()
         }
         clearPeriodShortcut()
+        if !suggestionsEnabled {
+            abandonChineseComposition()
+            return .insert(" ")
+        }
         let text = engine.processSpace() ?? " "
         composition = engine.composition
         syncCandidatePanelVisibility()
@@ -338,6 +354,10 @@ public final class TypingSessionController: ObservableObject {
         if language == .english {
             return commitEnglishWord(suffix: "\n")
         }
+        if !suggestionsEnabled {
+            abandonChineseComposition()
+            return .insert("\n")
+        }
         let text = engine.processReturn() ?? "\n"
         composition = engine.composition
         syncCandidatePanelVisibility()
@@ -349,6 +369,9 @@ public final class TypingSessionController: ObservableObject {
         if language == .english {
             return selectEnglishCandidate(at: index)
         }
+        if !suggestionsEnabled {
+            return .none
+        }
         guard composition.candidates.indices.contains(index) else { return .none }
         // Display order may put phrases before first-syllable chars; select by engine index.
         let engineIndex = composition.candidates[index].engineIndex
@@ -360,6 +383,13 @@ public final class TypingSessionController: ObservableObject {
         return text.isEmpty ? .none : .insert(text)
     }
 
+    /// Drop in-flight pinyin so secure fields cannot commit into userdb.
+    private func abandonChineseComposition() {
+        engineStorage?.clearComposition()
+        composition = .empty
+        isCandidatePanelExpanded = false
+    }
+
     // MARK: - English
 
     private func handleEnglishSpace() -> TypingOutput {