diff --git a/.vscode/settings.json b/.vscode/settings.json
index 460d5c5..ec42c3f 100644
--- a/.vscode/settings.json
+++ b/.vscode/settings.json
@@ -29,5 +29,6 @@
     "editor.formatOnSave": true,
     "editor.defaultFormatter": "esbenp.prettier-vscode",
     "editor.maxTokenizationLineLength": 2500
-  }
+  },
+  "vue3snippets.enable-compile-vue-file-on-did-save-code": false
 }
\ No newline at end of file
diff --git a/docs/.vitepress/theme/components/SentenceAudio.vue b/docs/.vitepress/theme/components/SentenceAudio.vue
index 6cc2588..ee1c5a8 100644
--- a/docs/.vitepress/theme/components/SentenceAudio.vue
+++ b/docs/.vitepress/theme/components/SentenceAudio.vue
@@ -15,15 +15,7 @@
 import { useTemplateRef } from "vue";
 import TTS from "./TTS.vue";
 import AudioButton from "./AudioButton.vue";
-
-export interface IVoc {
-  ko: string;
-  audio?: string;
-  en: string;
-  usages?: IVoc[];
-  notes?: string;
-  examples?: IVoc[];
-}
+import { IVoc } from "../types.ts";
 
 defineProps<{
   v: IVoc;
diff --git a/docs/.vitepress/theme/components/VocabQuiz.vue b/docs/.vitepress/theme/components/VocabQuiz.vue
index a0b3342..7169661 100644
--- a/docs/.vitepress/theme/components/VocabQuiz.vue
+++ b/docs/.vitepress/theme/components/VocabQuiz.vue
@@ -57,7 +57,7 @@
       <nav>
         <label v-for="c in vCats" :key="c">
           <input type="checkbox" :name="c" checked @change="updateCats(c)" />
-          {{ c.replace("_", " ") }}
+          {{ c.replace(/_/g, " ") }}
         </label>
       </nav>
       <nav>
@@ -99,8 +99,10 @@ import {
   useTemplateRef,
   watch,
 } from "vue";
-import SentenceAudio, { IVoc } from "./SentenceAudio.vue";
+import yaml from "yaml";
+import SentenceAudio from "./SentenceAudio.vue";
 import { supabase } from "../supabase.ts";
+import { IVoc, Voc } from "../types.ts";
 
 const { fmKey = "vocabulary" } = defineProps<{
   fmKey?: string;
@@ -157,7 +159,7 @@ watch(isKoFirst, () => {
 watch(isEdit, () => {
   if (isEdit.value) {
     const { ko, ...vContent } = v.value;
-    vEditContent.value = JSON.stringify(vContent, null, 2);
+    vEditContent.value = yaml.stringify(vContent);
   } else {
     vEditContent.value = "";
   }
@@ -240,7 +242,7 @@ function updateCats(cat: string) {
 
 async function onVContentSave() {
   const oldV = v.value;
-  const newV = { ko: oldV.ko, ...JSON.parse(vEditContent.value) };
+  const newV = Voc.parse({ ko: oldV.ko, ...yaml.parse(vEditContent.value) });
 
   let key = "";
   let vKey = oldV.ko;
@@ -257,7 +259,8 @@ async function onVContentSave() {
       vCount.set(v.ko, i + 1);
 
       if (oldV.ko === v.ko && oldV.en === v.en) {
-        key = k;
+        // TODO: handling multiple fmKey comma-separated
+        key = JSON.stringify([fmKey, k]);
         vKey = vK;
 
         vocabulary[k][i_vs] = newV;
diff --git a/docs/.vitepress/theme/types.ts b/docs/.vitepress/theme/types.ts
new file mode 100644
index 0000000..bfeb097
--- /dev/null
+++ b/docs/.vitepress/theme/types.ts
@@ -0,0 +1,16 @@
+import * as z from "zod";
+
+export const Voc = z.object({
+  ko: z.string(),
+  audio: z.string().optional(),
+  en: z.string(),
+  get usage() {
+    return z.array(Voc).optional();
+  },
+  notes: z.string().optional(),
+  get examples() {
+    return z.array(Voc).optional();
+  },
+});
+
+export type IVoc = z.infer<typeof Voc>;
diff --git a/docs/howtostudykorean/unit-1/05-tenses.md b/docs/howtostudykorean/unit-1/05-tenses.md
index 177e895..f7a5713 100644
--- a/docs/howtostudykorean/unit-1/05-tenses.md
+++ b/docs/howtostudykorean/unit-1/05-tenses.md
@@ -420,7 +420,7 @@ vocabulary:
       examples:
         - ko: 우리 집은 너무 **멀어요**
           en: Our home is very **far**
-        - ko: 저는 먼 병원에 갔어요
+        - ko: 저는 먼 **병원에** 갔어요
           en: I went to a **far away** hospital (a hospital that is **far away**)
 
     - ko: 마르다
@@ -440,7 +440,7 @@ vocabulary:
       examples:
         - ko: 저와 저의 아버지는 너무 **비슷해요**
           en: My father and I are very **similar**
-        - ko: 저는 친구와 비슷해요
+        - ko: 저는 친구와 **비슷해요**
           en: I am **similar** to my friend
 
     - ko: 싫다
@@ -1245,7 +1245,7 @@ Example:
 Example:
 
 - &NoBreak;<TTS class="md">우리 집은 너무 **멀어요**</TTS> = <span class="md spoiler">Our home is very **far**</span>
-- &NoBreak;<TTS class="md">저는 먼 병원에 갔어요</TTS> = <span class="md spoiler">I went to a **far away** hospital (a hospital that is **far away**)</span>
+- &NoBreak;<TTS class="md">저는 먼 **병원에** 갔어요</TTS> = <span class="md spoiler">I went to a **far away** hospital (a hospital that is **far away**)</span>
 
 </Details>
 
@@ -1274,7 +1274,7 @@ The pronunciation of this word is closer to “비스타다”
 Examples:
 
 - &NoBreak;<TTS class="md">저와 저의 아버지는 너무 **비슷해요**</TTS> = <span class="md spoiler">My father and I are very **similar**</span>
-- &NoBreak;<TTS class="md">저는 친구와 비슷해요</TTS> = <span class="md spoiler">I am **similar** to my friend</span>
+- &NoBreak;<TTS class="md">저는 친구와 **비슷해요**</TTS> = <span class="md spoiler">I am **similar** to my friend</span>
 
 </Details>
 
diff --git a/docs/howtostudykorean/unit-1/13-and-with.md b/docs/howtostudykorean/unit-1/13-and-with.md
index 592fb88..4a7c156 100644
--- a/docs/howtostudykorean/unit-1/13-and-with.md
+++ b/docs/howtostudykorean/unit-1/13-and-with.md
@@ -67,7 +67,7 @@ vocabulary:
       audio: https://www.howtostudykorean.com/wp-content/uploads/2015/11/Lesson13v6.mp3
       en: underground
       examples:
-        - ko: 차는 지하 **주차장**에 있어요
+        - ko: 차는 **지하** 주차장에 있어요
           en: The car is in the **underground** parking lot
 
     - ko: 빵
@@ -80,7 +80,7 @@ vocabulary:
           en: I made **bread** for my friend
         - ko: 우리는 **빵**을 같이 먹었어요
           en: We ate **bread** together
-        - ko: 애기는 **밥**하고 빵을 먹었어요
+        - ko: 애기는 밥하고 **빵**을 먹었어요
           en: The baby ate rice and **bread**
 
     - ko: 쓰레기
@@ -291,7 +291,7 @@ vocabulary:
       examples:
         - ko: 우리가 **늦**어서 죄송해요
           en: Sorry we arrived **late**
-        - ko: 우리는 늦은 저녁을 먹었어요
+        - ko: 우리는 **늦**은 저녁을 먹었어요
           en: We ate a **late** dinner
         - ko: 그녀는 언제나 **늦**게 와요
           en: She comes **late** every time
@@ -434,7 +434,7 @@ vocabulary:
           en: I want to eat what we ate **(together)** last time
         - ko: 이 일을 **같이** 하고 싶으면 우리는 협조해야 돼요
           en: If we want to do this job **together**, we have to cooperate
-        - ko: 우리 학교에서 학생들은 역사와 지리를 같이 배워요
+        - ko: 우리 학교에서 학생들은 역사와 지리를 **같이** 배워요
           en: At our school, students learn history and geography **together**
 ---
 
@@ -571,7 +571,7 @@ Common Usages:
 
 Examples:
 
-- 차는 지하 **주차장**에 있어요 = <span class="md spoiler">The car is in the **underground** parking lot</span>
+- 차는 **지하** 주차장에 있어요 = <span class="md spoiler">The car is in the **underground** parking lot</span>
 
 </Details>
 
@@ -589,7 +589,7 @@ Example:
 - 저는 **빵**을 먹고 싶어요 = <span class="md spoiler">I want to eat **bread**</span>
 - 저는 친구를 위해 **빵**을 만들었어요 = <span class="md spoiler">I made **bread** for my friend</span>
 - 우리는 **빵**을 같이 먹었어요 = <span class="md spoiler">We ate **bread** together</span>
-- 애기는 **밥**하고 빵을 먹었어요 = <span class="md spoiler">The baby ate rice and **bread**</span>
+- 애기는 밥하고 **빵**을 먹었어요 = <span class="md spoiler">The baby ate rice and **bread**</span>
 
 </Details>
 
@@ -927,7 +927,7 @@ This is often irrelevant, but 늦다 is both <span class="md spoiler">a verb and
 
 It is often used as an adjective to describe a time that is late. For example:
 
-- 우리는 늦은 저녁을 먹었어요 = <span class="md spoiler">We ate a **late** dinner</span>
+- 우리는 **늦**은 저녁을 먹었어요 = <span class="md spoiler">We ate a **late** dinner</span>
 
 As an adjective, ~게 is often added to it in order to create <span class="md spoiler">an adverb</span>. For example:
 
@@ -1136,7 +1136,7 @@ Examples:
 - 엄마가 우리랑 **같이** 못 먹어서 안타까워요 = <span class="md spoiler">It’s too bad that your mom can’t eat **together** (with us)</span>
 - 나는 우리가 지난 번에 **같이** 먹은 것을 먹고 싶어 = <span class="md spoiler">I want to eat what we ate **(together)** last time</span>
 - 이 일을 **같이** 하고 싶으면 우리는 협조해야 돼요 = <span class="md spoiler">If we want to do this job **together**, we have to cooperate</span>
-- 우리 학교에서 학생들은 역사와 지리를 같이 배워요 = <span class="md spoiler">At our school, students learn history and geography **together**</span>
+- 우리 학교에서 학생들은 역사와 지리를 **같이** 배워요 = <span class="md spoiler">At our school, students learn history and geography **together**</span>
 
 </Details>
 
diff --git a/package.json b/package.json
index cde8c29..93175d9 100644
--- a/package.json
+++ b/package.json
@@ -27,6 +27,8 @@
   "dependencies": {
     "@supabase/supabase-js": "^2.110.5",
     "pdfjs-dist": "^5.7.284",
-    "tauri-plugin-tts-api": "^0.1.11"
+    "tauri-plugin-tts-api": "^0.1.11",
+    "yaml": "^2.9.0",
+    "zod": "^4.4.3"
   }
 }
\ No newline at end of file
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index c96fe89..de8f089 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -17,13 +17,19 @@ importers:
       tauri-plugin-tts-api:
         specifier: ^0.1.11
         version: 0.1.11
+      yaml:
+        specifier: ^2.9.0
+        version: 2.9.0
+      zod:
+        specifier: ^4.4.3
+        version: 4.4.3
     devDependencies:
       '@tauri-apps/cli':
         specifier: ^2.11.4
         version: 2.11.4
       vitepress:
         specifier: 2.0.0-alpha.17
-        version: 2.0.0-alpha.17(postcss@8.5.16)
+        version: 2.0.0-alpha.17(postcss@8.5.16)(yaml@2.9.0)
       vue:
         specifier: ^3.5.39
         version: 3.5.39
@@ -950,6 +956,14 @@ packages:
       typescript:
         optional: true
 
+  yaml@2.9.0:
+    resolution: {integrity: sha512-2AvhNX3mb8zd6Zy7INTtSpl1F15HW6Wnqj0srWlkKLcpYl/gMIMJiyuGq2KeI2YFxUPjdlB+3Lc10seMLtL4cA==}
+    engines: {node: '>= 14.6'}
+    hasBin: true
+
+  zod@4.4.3:
+    resolution: {integrity: sha512-ytENFjIJFl2UwYglde2jchW2Hwm4GJFLDiSXWdTrJQBIN9Fcyp7n4DhxJEiWNAJMV1/BqWfW/kkg71UDcHJyTQ==}
+
   zwitch@2.0.4:
     resolution: {integrity: sha512-bXE4cR/kVZhKZX/RjPEflHaKVhUVl85noU3v6b8apfQEc1x4A+zBxjZ4lN8LqGd6WZ3dl98pY4o717VFmoPp+A==}
 
@@ -1329,10 +1343,10 @@ snapshots:
 
   '@ungap/structured-clone@1.3.2': {}
 
-  '@vitejs/plugin-vue@6.0.7(vite@7.3.6)(vue@3.5.39)':
+  '@vitejs/plugin-vue@6.0.7(vite@7.3.6(yaml@2.9.0))(vue@3.5.39)':
     dependencies:
       '@rolldown/pluginutils': 1.0.1
-      vite: 7.3.6
+      vite: 7.3.6(yaml@2.9.0)
       vue: 3.5.39
 
   '@vue/compiler-core@3.5.39':
@@ -1683,7 +1697,7 @@ snapshots:
       '@types/unist': 3.0.3
       vfile-message: 4.0.3
 
-  vite@7.3.6:
+  vite@7.3.6(yaml@2.9.0):
     dependencies:
       esbuild: 0.28.1
       fdir: 6.5.0(picomatch@4.0.5)
@@ -1693,8 +1707,9 @@ snapshots:
       tinyglobby: 0.2.17
     optionalDependencies:
       fsevents: 2.3.3
+      yaml: 2.9.0
 
-  vitepress@2.0.0-alpha.17(postcss@8.5.16):
+  vitepress@2.0.0-alpha.17(postcss@8.5.16)(yaml@2.9.0):
     dependencies:
       '@docsearch/css': 4.6.3
       '@docsearch/js': 4.6.3
@@ -1704,7 +1719,7 @@ snapshots:
       '@shikijs/transformers': 3.23.0
       '@shikijs/types': 3.23.0
       '@types/markdown-it': 14.1.2
-      '@vitejs/plugin-vue': 6.0.7(vite@7.3.6)(vue@3.5.39)
+      '@vitejs/plugin-vue': 6.0.7(vite@7.3.6(yaml@2.9.0))(vue@3.5.39)
       '@vue/devtools-api': 8.1.5
       '@vue/shared': 3.5.39
       '@vueuse/core': 14.3.0(vue@3.5.39)
@@ -1713,7 +1728,7 @@ snapshots:
       mark.js: 8.11.1
       minisearch: 7.2.0
       shiki: 3.23.0
-      vite: 7.3.6
+      vite: 7.3.6(yaml@2.9.0)
       vue: 3.5.39
     optionalDependencies:
       postcss: 8.5.16
@@ -1750,4 +1765,8 @@ snapshots:
       '@vue/server-renderer': 3.5.39(vue@3.5.39)
       '@vue/shared': 3.5.39
 
+  yaml@2.9.0: {}
+
+  zod@4.4.3: {}
+
   zwitch@2.0.4: {}