diff --git a/README.md b/README.md
index c203662d..be54d22b 100644
--- a/README.md
+++ b/README.md
@@ -10,6 +10,7 @@
 
 ## 主要な変更点
 
+- 投稿言語を自動検出して外国語の投稿に翻訳ボタンを表示する設定を追加
 - モバイル表示の下部のウィジェットボタンを再読み込みボタンに変更可能に
   - スマートフォンでウィジェットは使わないけど再読み込みはたくさんする人はいそう
 - モバイル表示の下部のチャットボタンをアカウント切り替えボタンに変更可能に
diff --git a/locales/en-US.yml b/locales/en-US.yml
index 1ba4b75d..f6d152a2 100644
--- a/locales/en-US.yml
+++ b/locales/en-US.yml
@@ -1142,6 +1142,7 @@ deletePasskeys: "Delete passkeys"
 delete2faConfirm: "This will irreversibly delete 2FA on this account. Proceed?"
 deletePasskeysConfirm: "This will irreversibly delete all passkeys and security keys on this account. Proceed?"
 inputNotMatch: "Input does not match"
+detectPostLanguage: "Automatically detect the language and show a translate button for non-English posts"
 
 _sensitiveMediaDetection:
   description: "Reduces the effort of server moderation through automatically recognizing
diff --git a/locales/ja-JP.yml b/locales/ja-JP.yml
index f0908472..e8cf2d1c 100644
--- a/locales/ja-JP.yml
+++ b/locales/ja-JP.yml
@@ -995,6 +995,7 @@ forMobile: "モバイル向け"
 replaceChatButtonWithAccountButton: "画面下部のチャットのボタンをアカウント切り替えボタンに変更する"
 replaceWidgetsButtonWithReloadButton: "画面下部のウィジェットのボタンを再読み込みボタンに変更する"
 addRe: "閲覧注意の投稿への返信で、注釈の先頭に\"re:\"を追加する"
+detectPostLanguage: "投稿の言語を自動検出し、外国語の投稿に翻訳ボタンを表示する"
 
 _sensitiveMediaDetection:
   description: "機械学習を使って自動でセンシティブなメディアを検出し、モデレーションに役立てられます。サーバーの負荷が少し増えます。"
diff --git a/packages/client/package.json b/packages/client/package.json
index 43983c46..46aa303a 100644
--- a/packages/client/package.json
+++ b/packages/client/package.json
@@ -83,6 +83,7 @@
 		"three": "0.146.0",
 		"throttle-debounce": "5.0.0",
 		"tinycolor2": "1.6.0",
+		"tinyld": "1.3.4",
 		"tsc-alias": "1.8.7",
 		"tsconfig-paths": "4.2.0",
 		"twemoji-parser": "14.0.0",
diff --git a/packages/client/src/components/MkNote.vue b/packages/client/src/components/MkNote.vue
index face71b6..f0a287c0 100644
--- a/packages/client/src/components/MkNote.vue
+++ b/packages/client/src/components/MkNote.vue
@@ -219,6 +219,14 @@
 						<i class="ph-minus ph-bold ph-lg"></i>
 					</button>
 					<XQuoteButton class="button" :note="appearNote" />
+					<button
+						v-if="isForeignLanguage && translation == null"
+						class="button _button accent"
+						@click.stop="translate"
+						v-tooltip.noDelay.bottom="i18n.ts.translate"
+					>
+						<i class="ph-translate ph-bold ph-lg"></i>
+					</button>
 					<button
 						ref="menuButton"
 						v-tooltip.noDelay.bottom="i18n.ts.more"
@@ -259,6 +267,7 @@ import { computed, inject, onMounted, onUnmounted, reactive, ref } from "vue";
 import * as mfm from "mfm-js";
 import type { Ref } from "vue";
 import type * as misskey from "firefish-js";
+import { detect as detectLanguage } from "tinyld";
 import MkNoteSub from "@/components/MkNoteSub.vue";
 import MkSubNoteContent from "./MkSubNoteContent.vue";
 import XNoteHeader from "@/components/MkNoteHeader.vue";
@@ -350,6 +359,35 @@ const translating = ref(false);
 const enableEmojiReactions = defaultStore.state.enableEmojiReactions;
 const expandOnNoteClick = defaultStore.state.expandOnNoteClick;
 
+const purifyMFM = (src) => {
+	const nodes = mfm.parse(src);
+	const filtered = mfm.extract(nodes, (node) => {
+		return ["text", "bold", "center", "small", "italic", "strike"].includes(
+			node.type,
+		);
+	});
+	return mfm.toString(filtered);
+};
+const isForeignLanguage = (() => {
+	if (!defaultStore.state.detectPostLanguage || !appearNote.text)
+		return false;
+	const text = purifyMFM(appearNote.text).trim();
+	if (!text) return false;
+	const uiLanguage = (
+		localStorage.getItem("lang") || navigator.language
+	).slice(0, 2);
+	return detectLanguage(text) !== uiLanguage;
+})();
+const translate = async () => {
+	if (translation.value != null) return;
+	translating.value = true;
+	translation.value = await os.api("notes/translate", {
+		noteId: appearNote.id,
+		targetLang: localStorage.getItem("lang") || navigator.language,
+	});
+	translating.value = false;
+};
+
 const keymap = {
 	r: () => reply(true),
 	"e|a|plus": () => react(true),
@@ -914,6 +952,10 @@ defineExpose({
 					&.reacted {
 						color: var(--accent);
 					}
+
+					&.accent {
+						color: var(--accent);
+					}
 				}
 			}
 		}
diff --git a/packages/client/src/components/MkNoteSub.vue b/packages/client/src/components/MkNoteSub.vue
index 690ba62a..1929a623 100644
--- a/packages/client/src/components/MkNoteSub.vue
+++ b/packages/client/src/components/MkNoteSub.vue
@@ -124,6 +124,14 @@
 						<i class="ph-minus ph-bold ph-lg"></i>
 					</button>
 					<XQuoteButton class="button" :note="appearNote" />
+					<button
+						v-if="isForeignLanguage && translation == null"
+						class="button _button accent"
+						@click.stop="translate"
+						v-tooltip.noDelay.bottom="i18n.ts.translate"
+					>
+						<i class="ph-translate ph-bold ph-lg"></i>
+					</button>
 					<button
 						ref="menuButton"
 						v-tooltip.noDelay.bottom="i18n.ts.more"
@@ -180,6 +188,8 @@
 import { inject, ref } from "vue";
 import type { Ref } from "vue";
 import * as misskey from "firefish-js";
+import * as mfm from "mfm-js";
+import { detect as detectLanguage } from "tinyld";
 import XNoteHeader from "@/components/MkNoteHeader.vue";
 import MkSubNoteContent from "@/components/MkSubNoteContent.vue";
 import XReactionsViewer from "@/components/MkReactionsViewer.vue";
@@ -265,6 +275,35 @@ const replies: misskey.entities.Note[] =
 const enableEmojiReactions = defaultStore.state.enableEmojiReactions;
 const expandOnNoteClick = defaultStore.state.expandOnNoteClick;
 
+const purifyMFM = (src) => {
+	const nodes = mfm.parse(src);
+	const filtered = mfm.extract(nodes, (node) => {
+		return ["text", "bold", "center", "small", "italic", "strike"].includes(
+			node.type,
+		);
+	});
+	return mfm.toString(filtered);
+};
+const isForeignLanguage = (() => {
+	if (!defaultStore.state.detectPostLanguage || !appearNote.text)
+		return false;
+	const text = purifyMFM(appearNote.text).trim();
+	if (!text) return false;
+	const uiLanguage = (
+		localStorage.getItem("lang") || navigator.language
+	).slice(0, 2);
+	return detectLanguage(text) !== uiLanguage;
+})();
+const translate = async () => {
+	if (translation.value != null) return;
+	translating.value = true;
+	translation.value = await os.api("notes/translate", {
+		noteId: appearNote.id,
+		targetLang: localStorage.getItem("lang") || navigator.language,
+	});
+	translating.value = false;
+};
+
 useNoteCapture({
 	rootEl: el,
 	note: $$(appearNote),
@@ -522,6 +561,10 @@ function noteClick(e) {
 					&.reacted {
 						color: var(--accent);
 					}
+
+					&.accent {
+						color: var(--accent);
+					}
 				}
 			}
 		}
diff --git a/packages/client/src/pages/settings/general.vue b/packages/client/src/pages/settings/general.vue
index 9b832905..34da3adf 100644
--- a/packages/client/src/pages/settings/general.vue
+++ b/packages/client/src/pages/settings/general.vue
@@ -77,6 +77,12 @@
 					{{ i18n.ts.reflectMayTakeTime }}</template
 				></FormSwitch
 			>
+			<FormSwitch v-model="detectPostLanguage" class="_formBlock"
+				>{{ i18n.ts.detectPostLanguage
+				}}<span class="_beta">{{
+					i18n.ts.originalFeature
+				}}</span></FormSwitch
+			>
 			<FormSwitch v-model="addRe" class="_formBlock"
 				>{{ i18n.ts.addRe
 				}}<span class="_beta">{{
@@ -412,6 +418,9 @@ const replaceWidgetsButtonWithReloadButton = computed(
 	defaultStore.makeGetterSetter("replaceWidgetsButtonWithReloadButton"),
 );
 const addRe = computed(defaultStore.makeGetterSetter("addRe"));
+const detectPostLanguage = computed(
+	defaultStore.makeGetterSetter("detectPostLanguage"),
+);
 
 watch(swipeOnDesktop, () => {
 	defaultStore.set("swipeOnMobile", true);
diff --git a/packages/client/src/store.ts b/packages/client/src/store.ts
index af45f7b5..d3ebaf2f 100644
--- a/packages/client/src/store.ts
+++ b/packages/client/src/store.ts
@@ -362,6 +362,10 @@ export const defaultStore = markRaw(
 			where: "account",
 			default: true,
 		},
+		detectPostLanguage: {
+			where: "deviceAccount",
+			default: true,
+		},
 	}),
 );
 
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 01ceac62..65634d05 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -842,6 +842,9 @@ importers:
       tinycolor2:
         specifier: 1.6.0
         version: 1.6.0
+      tinyld:
+        specifier: 1.3.4
+        version: 1.3.4
       tsc-alias:
         specifier: 1.8.7
         version: 1.8.7
@@ -17582,6 +17585,12 @@ packages:
     resolution: {integrity: sha512-XPaBkWQJdsf3pLKJV9p4qN/S+fm2Oj8AIPo1BTUhg5oxkvm9+SVEGFdhyOz7tTdUTfvxMiAs4sp6/eZO2Ew+pw==}
     dev: true
 
+  /tinyld@1.3.4:
+    resolution: {integrity: sha512-u26CNoaInA4XpDU+8s/6Cq8xHc2T5M4fXB3ICfXPokUQoLzmPgSZU02TAkFwFMJCWTjk53gtkS8pETTreZwCqw==}
+    engines: {node: '>= 12.10.0', npm: '>= 6.12.0', yarn: '>= 1.20.0'}
+    hasBin: true
+    dev: true
+
   /titleize@3.0.0:
     resolution: {integrity: sha512-KxVu8EYHDPBdUYdKZdKtU2aj2XfEx9AfjXxE/Aj0vT06w2icA09Vus1rh6eSu1y01akYg6BjIK/hxyLJINoMLQ==}
     engines: {node: '>=12'}