diff --git a/packages/hikkaku/src/blocks/index.ts b/packages/hikkaku/src/blocks/index.ts
index 0eebc3f..3ace958 100644
--- a/packages/hikkaku/src/blocks/index.ts
+++ b/packages/hikkaku/src/blocks/index.ts
@@ -9,3 +9,6 @@ export * from './pen'
 export * from './procedures'
 export * from './sensing'
 export * from './sound'
+export * from './text2speech'
+export * from './translate'
+export * from './videosensing'
diff --git a/packages/hikkaku/src/blocks/text2speech.test.ts b/packages/hikkaku/src/blocks/text2speech.test.ts
new file mode 100644
index 0000000..7e173d7
--- /dev/null
+++ b/packages/hikkaku/src/blocks/text2speech.test.ts
@@ -0,0 +1,21 @@
+import { describe, expect, test } from 'vite-plus/test'
+import { block, createBlocks } from '../core/composer'
+import { setLanguage, setVoice, speakAndWait } from './text2speech'
+
+describe('blocks/text2speech', () => {
+  test('creates text to speech extension blocks', () => {
+    const blocks = createBlocks(() => {
+      block('event_whenflagclicked', { topLevel: true })
+      setVoice('TENOR')
+      setLanguage('ja')
+      speakAndWait('hello')
+    })
+
+    const opcodes = Object.values(blocks).map((b) => b.opcode)
+    expect(opcodes).toContain('text2speech_setVoice')
+    expect(opcodes).toContain('text2speech_menu_voices')
+    expect(opcodes).toContain('text2speech_setLanguage')
+    expect(opcodes).toContain('text2speech_menu_languages')
+    expect(opcodes).toContain('text2speech_speakAndWait')
+  })
+})
diff --git a/packages/hikkaku/src/blocks/text2speech.ts b/packages/hikkaku/src/blocks/text2speech.ts
new file mode 100644
index 0000000..8e65ed1
--- /dev/null
+++ b/packages/hikkaku/src/blocks/text2speech.ts
@@ -0,0 +1,103 @@
+import { InputType } from 'sb3-types/enum'
+import { fromPrimitiveSource, menuInput } from '../core/block-helper'
+import { block, valueBlock } from '../core/composer'
+import type { HikkakuString, PrimitiveSource } from '../core/types'
+
+export type TextToSpeechVoice =
+  | 'ALTO'
+  | 'TENOR'
+  | 'SQUEAK'
+  | 'GIANT'
+  | 'KITTEN'
+  | 'GOOGLE'
+
+/**
+ * Speaks text and waits until completion.
+ *
+ * Input: `words`.
+ * Output: Scratch statement block definition that is appended to the current script stack.
+ *
+ * @param words See function signature for accepted input values.
+ * @returns Scratch statement block definition that is appended to the current script stack.
+ * @example
+ * ```ts
+ * import { speakAndWait } from 'hikkaku/blocks'
+ *
+ * speakAndWait('hello')
+ * ```
+ */
+export const speakAndWait = (words: PrimitiveSource<HikkakuString>) => {
+  return block('text2speech_speakAndWait', {
+    inputs: {
+      WORDS: fromPrimitiveSource(InputType.String, words, 'hello'),
+    },
+  })
+}
+
+/**
+ * Sets the text-to-speech voice.
+ *
+ * Input: `voice`.
+ * Output: Scratch statement block definition that is appended to the current script stack.
+ *
+ * @param voice See function signature for accepted input values.
+ * @returns Scratch statement block definition that is appended to the current script stack.
+ * @example
+ * ```ts
+ * import { setVoice } from 'hikkaku/blocks'
+ *
+ * setVoice('TENOR')
+ * ```
+ */
+export function setVoice(voice: TextToSpeechVoice): ReturnType<typeof block>
+export function setVoice(
+  voice: PrimitiveSource<HikkakuString>,
+): ReturnType<typeof block>
+export function setVoice(voice: PrimitiveSource<HikkakuString>) {
+  return block('text2speech_setVoice', {
+    inputs: {
+      VOICE: menuInput(voice, menuOfTextToSpeechVoice),
+    },
+  })
+}
+
+export const menuOfTextToSpeechVoice = (voice: TextToSpeechVoice = 'ALTO') => {
+  return valueBlock<HikkakuString>('text2speech_menu_voices', {
+    fields: {
+      voices: [voice, null],
+    },
+    isShadow: true,
+  })
+}
+
+/**
+ * Sets the text-to-speech language.
+ *
+ * Input: `language`.
+ * Output: Scratch statement block definition that is appended to the current script stack.
+ *
+ * @param language See function signature for accepted input values.
+ * @returns Scratch statement block definition that is appended to the current script stack.
+ * @example
+ * ```ts
+ * import { setLanguage } from 'hikkaku/blocks'
+ *
+ * setLanguage('ja')
+ * ```
+ */
+export const setLanguage = (language: PrimitiveSource<HikkakuString>) => {
+  return block('text2speech_setLanguage', {
+    inputs: {
+      LANGUAGE: menuInput(language, menuOfTextToSpeechLanguage),
+    },
+  })
+}
+
+export const menuOfTextToSpeechLanguage = (language: string = 'en') => {
+  return valueBlock<HikkakuString>('text2speech_menu_languages', {
+    fields: {
+      languages: [language, null],
+    },
+    isShadow: true,
+  })
+}
diff --git a/packages/hikkaku/src/blocks/translate.test.ts b/packages/hikkaku/src/blocks/translate.test.ts
new file mode 100644
index 0000000..8afad74
--- /dev/null
+++ b/packages/hikkaku/src/blocks/translate.test.ts
@@ -0,0 +1,19 @@
+import { describe, expect, test } from 'vite-plus/test'
+import { block, createBlocks } from '../core/composer'
+import { say } from './looks'
+import { getViewerLanguage, translate } from './translate'
+
+describe('blocks/translate', () => {
+  test('creates translate extension blocks', () => {
+    const blocks = createBlocks(() => {
+      block('event_whenflagclicked', { topLevel: true })
+      say(translate('hello', 'ja'))
+      say(getViewerLanguage())
+    })
+
+    const opcodes = Object.values(blocks).map((b) => b.opcode)
+    expect(opcodes).toContain('translate_getTranslate')
+    expect(opcodes).toContain('translate_menu_languages')
+    expect(opcodes).toContain('translate_getViewerLanguage')
+  })
+})
diff --git a/packages/hikkaku/src/blocks/translate.ts b/packages/hikkaku/src/blocks/translate.ts
new file mode 100644
index 0000000..9c8750c
--- /dev/null
+++ b/packages/hikkaku/src/blocks/translate.ts
@@ -0,0 +1,59 @@
+import { InputType } from 'sb3-types/enum'
+import { fromPrimitiveSource, menuInput } from '../core/block-helper'
+import { valueBlock } from '../core/composer'
+import type { HikkakuString, PrimitiveSource } from '../core/types'
+
+/**
+ * Translates words to a target language.
+ *
+ * Input: `words`, `language`.
+ * Output: Scratch reporter block definition that can be used as an input value in other blocks.
+ *
+ * @param words See function signature for accepted input values.
+ * @param language See function signature for accepted input values.
+ * @returns Scratch reporter block definition that can be used as an input value in other blocks.
+ * @example
+ * ```ts
+ * import { translate } from 'hikkaku/blocks'
+ *
+ * translate('hello', 'ja')
+ * ```
+ */
+export const translate = (
+  words: PrimitiveSource<HikkakuString>,
+  language: PrimitiveSource<HikkakuString>,
+) => {
+  return valueBlock<HikkakuString>('translate_getTranslate', {
+    inputs: {
+      WORDS: fromPrimitiveSource(InputType.String, words, 'hello'),
+      LANGUAGE: menuInput(language, menuOfTranslateLanguage),
+    },
+  })
+}
+
+export const menuOfTranslateLanguage = (language: string = 'ja') => {
+  return valueBlock<HikkakuString>('translate_menu_languages', {
+    fields: {
+      languages: [language, null],
+    },
+    isShadow: true,
+  })
+}
+
+/**
+ * Returns viewer language.
+ *
+ * Input: none.
+ * Output: Scratch reporter block definition that can be used as an input value in other blocks.
+ *
+ * @returns Scratch reporter block definition that can be used as an input value in other blocks.
+ * @example
+ * ```ts
+ * import { getViewerLanguage } from 'hikkaku/blocks'
+ *
+ * getViewerLanguage()
+ * ```
+ */
+export const getViewerLanguage = () => {
+  return valueBlock<HikkakuString>('translate_getViewerLanguage', {})
+}
diff --git a/packages/hikkaku/src/blocks/videosensing.test.ts b/packages/hikkaku/src/blocks/videosensing.test.ts
new file mode 100644
index 0000000..481b8d1
--- /dev/null
+++ b/packages/hikkaku/src/blocks/videosensing.test.ts
@@ -0,0 +1,35 @@
+import { describe, expect, test } from 'vite-plus/test'
+import { createBlocks } from '../core/composer'
+import { say } from './looks'
+import {
+  setVideoTransparency,
+  videoOn,
+  videoToggle,
+  whenMotionGreaterThan,
+} from './videosensing'
+
+describe('blocks/videosensing', () => {
+  test('creates video sensing extension blocks', () => {
+    const blocks = createBlocks(() => {
+      whenMotionGreaterThan(10, () => {
+        setVideoTransparency(50)
+      })
+      say(videoOn('motion', 'this sprite'))
+      videoToggle('on')
+    })
+
+    const opcodes = Object.values(blocks).map((b) => b.opcode)
+    expect(opcodes).toContain('videoSensing_whenMotionGreaterThan')
+    expect(opcodes).toContain('videoSensing_videoOn')
+    expect(opcodes).toContain('videoSensing_menu_ATTRIBUTE')
+    expect(opcodes).toContain('videoSensing_menu_SUBJECT')
+    expect(opcodes).toContain('videoSensing_videoToggle')
+    expect(opcodes).toContain('videoSensing_menu_VIDEO_STATE')
+    expect(opcodes).toContain('videoSensing_setVideoTransparency')
+
+    const hat = Object.values(blocks).find(
+      (b) => b.opcode === 'videoSensing_whenMotionGreaterThan',
+    )
+    expect(hat?.topLevel).toBe(true)
+  })
+})
diff --git a/packages/hikkaku/src/blocks/videosensing.ts b/packages/hikkaku/src/blocks/videosensing.ts
new file mode 100644
index 0000000..4e6736b
--- /dev/null
+++ b/packages/hikkaku/src/blocks/videosensing.ts
@@ -0,0 +1,149 @@
+import { InputType } from 'sb3-types/enum'
+import { fromPrimitiveSource, menuInput } from '../core/block-helper'
+import { attachStack, block, valueBlock } from '../core/composer'
+import type {
+  HikkakuNumber,
+  HikkakuString,
+  PrimitiveSource,
+} from '../core/types'
+
+export type VideoSensingAttribute = 'motion' | 'direction'
+export type VideoSensingSubject = 'this sprite' | 'stage'
+export type VideoState = 'on' | 'off' | 'on-flipped'
+
+/**
+ * Runs when motion is greater than a threshold.
+ *
+ * Input: `reference`, `stack`.
+ * Output: Scratch statement block definition that is appended to the current script stack.
+ *
+ * @param reference See function signature for accepted input values.
+ * @param stack See function signature for accepted input values. Optional.
+ * @returns Scratch statement block definition that is appended to the current script stack.
+ * @example
+ * ```ts
+ * import { whenMotionGreaterThan } from 'hikkaku/blocks'
+ *
+ * whenMotionGreaterThan(10, () => {})
+ * ```
+ */
+export const whenMotionGreaterThan = (
+  reference: PrimitiveSource<HikkakuNumber>,
+  stack?: () => void,
+) => {
+  const res = block('videoSensing_whenMotionGreaterThan', {
+    topLevel: true,
+    inputs: {
+      REFERENCE: fromPrimitiveSource(InputType.Number, reference, 10),
+    },
+  })
+  attachStack(res.id, stack)
+  return res
+}
+
+/**
+ * Returns motion or direction detected from a subject.
+ *
+ * Input: `attribute`, `subject`.
+ * Output: Scratch reporter block definition that can be used as an input value in other blocks.
+ *
+ * @param attribute See function signature for accepted input values.
+ * @param subject See function signature for accepted input values.
+ * @returns Scratch reporter block definition that can be used as an input value in other blocks.
+ * @example
+ * ```ts
+ * import { videoOn } from 'hikkaku/blocks'
+ *
+ * videoOn('motion', 'this sprite')
+ * ```
+ */
+export const videoOn = (
+  attribute: PrimitiveSource<HikkakuString>,
+  subject: PrimitiveSource<HikkakuString>,
+) => {
+  return valueBlock<HikkakuNumber>('videoSensing_videoOn', {
+    inputs: {
+      ATTRIBUTE: menuInput(attribute, menuOfVideoSensingAttribute),
+      SUBJECT: menuInput(subject, menuOfVideoSensingSubject),
+    },
+  })
+}
+
+export const menuOfVideoSensingAttribute = (
+  attribute: VideoSensingAttribute = 'motion',
+) => {
+  return valueBlock<HikkakuString>('videoSensing_menu_ATTRIBUTE', {
+    fields: {
+      ATTRIBUTE: [attribute, null],
+    },
+    isShadow: true,
+  })
+}
+
+export const menuOfVideoSensingSubject = (
+  subject: VideoSensingSubject = 'this sprite',
+) => {
+  return valueBlock<HikkakuString>('videoSensing_menu_SUBJECT', {
+    fields: {
+      SUBJECT: [subject, null],
+    },
+    isShadow: true,
+  })
+}
+
+/**
+ * Turns video on/off/flipped.
+ *
+ * Input: `state`.
+ * Output: Scratch statement block definition that is appended to the current script stack.
+ *
+ * @param state See function signature for accepted input values.
+ * @returns Scratch statement block definition that is appended to the current script stack.
+ * @example
+ * ```ts
+ * import { videoToggle } from 'hikkaku/blocks'
+ *
+ * videoToggle('on')
+ * ```
+ */
+export const videoToggle = (state: PrimitiveSource<HikkakuString>) => {
+  return block('videoSensing_videoToggle', {
+    inputs: {
+      VIDEO_STATE: menuInput(state, menuOfVideoSensingState),
+    },
+  })
+}
+
+export const menuOfVideoSensingState = (state: VideoState = 'on') => {
+  return valueBlock<HikkakuString>('videoSensing_menu_VIDEO_STATE', {
+    fields: {
+      VIDEO_STATE: [state, null],
+    },
+    isShadow: true,
+  })
+}
+
+/**
+ * Sets video transparency.
+ *
+ * Input: `transparency`.
+ * Output: Scratch statement block definition that is appended to the current script stack.
+ *
+ * @param transparency See function signature for accepted input values.
+ * @returns Scratch statement block definition that is appended to the current script stack.
+ * @example
+ * ```ts
+ * import { setVideoTransparency } from 'hikkaku/blocks'
+ *
+ * setVideoTransparency(50)
+ * ```
+ */
+export const setVideoTransparency = (
+  transparency: PrimitiveSource<HikkakuNumber>,
+) => {
+  return block('videoSensing_setVideoTransparency', {
+    inputs: {
+      TRANSPARENCY: fromPrimitiveSource(InputType.Number, transparency, 50),
+    },
+  })
+}