diff --git a/app/core/hooks/event.ts b/app/core/hooks/event.ts
index 13296fbe9..c8c3ab380 100644
--- a/app/core/hooks/event.ts
+++ b/app/core/hooks/event.ts
@@ -2,6 +2,7 @@ import {onDeactivated, onMounted, onUnmounted, watch, type WatchSource} from 'vu
 import {emitter, EventKey} from '../utils/eventBus'
 import {useSettingStore} from '../stores'
 import {isMobile} from '../utils'
+import {shouldIgnoreDeadKeyCompositionSpace} from '../utils/dead-key-composition'
 import {Toast} from '@/base'
 
 const CODE_TO_CHAR: Record<string, string> = {
@@ -79,6 +80,9 @@ export function useWindowClick(cb: (e: PointerEvent) => void) {
   onDeactivated(remove)
 }
 
+// 组合状态（IME/死键）共享给全局 keydown 处理：组合进行中时空格是终结符而非分词符
+let isComposing = false
+
 export function useEventListener(type: string, listener: EventListenerOrEventListenerObject) {
   const invokeListener = (event: KeyboardEvent) => {
     if (typeof listener === 'function') {
@@ -145,7 +149,6 @@ export function useEventListener(type: string, listener: EventListenerOrEventLis
       }
 
       const hiddenInput = ensureMobileInput()
-      let isComposing = false
 
       const createSyntheticEvent = (payload: { key: string; code?: string; keyCode: number }) => {
         const base = {
@@ -174,11 +177,15 @@ export function useEventListener(type: string, listener: EventListenerOrEventLis
       const handleCompositionStart = () => {
         // console.log('handleCompositionStart',Date.now())
         isComposing = true
-        Toast.warning('请切换到英文输入')
       }
 
       const handleCompositionEnd = (event: CompositionEvent) => {
         isComposing = false
+        // 死键（´、`、^…）组合也走 composition 事件，但它们不是 IME；只有产出 CJK/全角
+        // 文本才是真正的输入法，此时才提示切换到英文，避免死键每次都弹警告
+        if (event.data && /[\u4e00-\u9fff\u3040-\u30ff\uac00-\ud7af\uff00-\uffef]/.test(event.data)) {
+          Toast.warning('请切换到英文输入')
+        }
         if (!event.data) {
           hiddenInput.value = ' '
           return
@@ -197,6 +204,9 @@ export function useEventListener(type: string, listener: EventListenerOrEventLis
       const handleInput = (event: InputEvent) => {
         // console.log('handleInput',event,Date.now())
         if (isComposing) return
+        // Firefox 的 input 事件晚于 compositionend 到达，此时输入框已被重置为哨兵 ' '，
+        // slice(-1) 会把哨兵空格派发成幽灵空格；组合字符已由 handleCompositionEnd 派发过
+        if (event.inputType === 'insertCompositionText' || event.inputType === 'insertFromComposition') return
         const target = event.target as HTMLInputElement | null
         if (!target) return
         let char = ''
@@ -317,6 +327,21 @@ export function useStartKeyboardEventListener() {
   const settingStore = useSettingStore()
 
   useEventListener('keydown', (e: KeyboardEvent) => {
+    // 组合进行中（死键/IME）的空格是"终结/取消"组合的键，不是分词空格，必须吞掉
+    if (isComposing && e.code === 'Space' && e.key === ' ') {
+      e.preventDefault()
+      return
+    }
+    // 死键布局（西班牙语/US-Intl）中 ' 的 keydown 是组合起点，组合空格的终结在此吞掉
+    if (shouldIgnoreDeadKeyCompositionSpace(e)) {
+      e.preventDefault()
+      return
+    }
+    // 死键本身不产生字符，字符由系统组合后经隐藏输入框 input 事件送入
+    if (e.key === 'Dead') {
+      e.preventDefault()
+      return
+    }
     // console.log('keydown', e)
     // debugger
     //解决无法复制、全选的问题
diff --git a/app/core/utils/dead-key-composition.ts b/app/core/utils/dead-key-composition.ts
new file mode 100644
index 000000000..a7ce791d5
--- /dev/null
+++ b/app/core/utils/dead-key-composition.ts
@@ -0,0 +1,29 @@
+/**
+ * 死键（dead key）处理：Chromium/Gecko 在死键布局（西班牙语、国际美式等）下把
+ * 死键报告为 key='Dead'。死键本身不产生字符，字符由系统组合后经隐藏输入框的
+ * input 事件送进输入逻辑；紧跟死键的空格是组合终结符，会被系统消费，不是分词空格。
+ */
+let lastKeyDownWasDeadKey = false
+
+/** 返回 true 表示这次空格是死键组合终结符，应吞掉；对其他键跟踪死键状态。 */
+export function shouldIgnoreDeadKeyCompositionSpace(event: {
+  key: string
+  code: string
+  ctrlKey?: boolean
+  metaKey?: boolean
+  altKey?: boolean
+}): boolean {
+  if (event.ctrlKey || event.metaKey || event.altKey) return false
+  if (event.code === 'Space' && event.key === ' ') {
+    const isTerminator = lastKeyDownWasDeadKey
+    lastKeyDownWasDeadKey = false
+    return isTerminator
+  }
+  lastKeyDownWasDeadKey = event.key === 'Dead'
+  return false
+}
+
+/** 复位内部状态，便于测试隔离。 */
+export function resetDeadKeyCompositionState(): void {
+  lastKeyDownWasDeadKey = false
+}
diff --git a/tests/unit/dead-key-composition.test.ts b/tests/unit/dead-key-composition.test.ts
new file mode 100644
index 000000000..a6efcbbde
--- /dev/null
+++ b/tests/unit/dead-key-composition.test.ts
@@ -0,0 +1,33 @@
+import { beforeEach, describe, expect, it } from 'vitest'
+import {
+  resetDeadKeyCompositionState,
+  shouldIgnoreDeadKeyCompositionSpace,
+} from '../../app/core/utils/dead-key-composition.ts'
+
+describe('dead key composition space swallowing', () => {
+  beforeEach(() => {
+    resetDeadKeyCompositionState()
+  })
+
+  it('swallows the space that terminates a dead-key composition (es / US-Intl, key=Dead)', () => {
+    expect(shouldIgnoreDeadKeyCompositionSpace({ key: 'Dead', code: 'Quote' })).toBe(false)
+    expect(shouldIgnoreDeadKeyCompositionSpace({ key: ' ', code: 'Space' })).toBe(true)
+    expect(shouldIgnoreDeadKeyCompositionSpace({ key: ' ', code: 'Space' })).toBe(false)
+  })
+
+  it('does not swallow a normal space after a regular letter (plain English layout)', () => {
+    expect(shouldIgnoreDeadKeyCompositionSpace({ key: 's', code: 'KeyS' })).toBe(false)
+    expect(shouldIgnoreDeadKeyCompositionSpace({ key: ' ', code: 'Space' })).toBe(false)
+  })
+
+  it('resets the dead key flag after any intermediate non-space key', () => {
+    expect(shouldIgnoreDeadKeyCompositionSpace({ key: 'Dead', code: 'Quote' })).toBe(false)
+    expect(shouldIgnoreDeadKeyCompositionSpace({ key: 'x', code: 'KeyX' })).toBe(false)
+    expect(shouldIgnoreDeadKeyCompositionSpace({ key: ' ', code: 'Space' })).toBe(false)
+  })
+
+  it('never swallows spaces pressed with modifiers', () => {
+    expect(shouldIgnoreDeadKeyCompositionSpace({ key: 'Dead', code: 'Quote' })).toBe(false)
+    expect(shouldIgnoreDeadKeyCompositionSpace({ key: ' ', code: 'Space', metaKey: true })).toBe(false)
+  })
+})