Speech AI - Pronunciation, STT & TTS

Measured conclusion: Deep-tested. L2 outcome: tools_ok.

Pronunciation scoring, speech-to-text, and text-to-speech for language learning

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Copy this into your MCP client config:

{
  "mcpServers": {
    "Speech AI - Pronunciation, STT & TTS": {
      "url": "https://apim-ai-apis.azure-api.net/mcp/pronunciation/mcp",
      "transport": "streamable-http"
    }
  }
}

Measured tools (10)

• assess_pronunciation read-only

  Assess English pronunciation quality from audio. Scores pronunciation at four levels: overall, sentence, word, and phoneme. Each score is 0-100. Phonemes are returned in both IPA and ARPAbet notation. Sub-300ms inference latency. Args: audio_base64: Base64-encoded audio data. Supports WAV, MP3, OGG, and WebM formats. text: The reference English text that the speaker was expected to read aloud. audio_format: Audio format hint — one of 'wav', 'mp3', 'ogg', 'webm'. Defaults to 'wav'. Returns: dict with keys: - overallScore (int 0-100): Overall pronunciation quality - sentenceScore (int 0-100): Sentence-level fluency and accuracy - words (list): Per-word scores, each containing: - word (str): The word - score (int 0-100): Word pronunciation score - phonemes (list): Per-phoneme scores with IPA/ARPAbet notation - decodedTranscript (str): What the model heard (ASR transcript) - transcript (str): Reference text - confidence (float 0-1): Scoring confidence - warnings (list[str]): Quality warnings if any - audioQuality (dict): Audio metrics (SNR, peak/RMS dB, etc.)

  Parameters:

  • audio_base64 (required) — string — Base64-encoded audio data. Supports WAV, MP3, OGG, and WebM formats.
  • text (required) — string — The reference English text that the speaker was expected to read aloud.
  • audio_format — string — Audio format hint — one of 'wav', 'mp3', 'ogg', 'webm'.

  Hints: read-only yes · destructive no · idempotent yes · open-world yes

• check_pronunciation_service read-only

  Check if the pronunciation assessment service is healthy and ready. Returns: dict with keys: - status (str): 'healthy' or error state - modelLoaded (bool): Whether the scoring model is loaded - version (str): API version

  Hints: read-only yes · destructive no · idempotent yes · open-world yes

• get_phoneme_inventory read-only

  Get the full phoneme inventory supported by the pronunciation scorer. Returns a list of all English phonemes the engine can assess, including ARPAbet symbol, IPA equivalent, example word, and phoneme category (vowel, consonant, diphthong). Returns: list of dicts, each with keys: - arpabet (str): ARPAbet symbol (e.g. 'AA', 'TH') - ipa (str): IPA notation - example (str): Example word containing the phoneme - category (str): vowel, consonant, or diphthong

  Hints: read-only yes · destructive no · idempotent yes · open-world no

• transcribe_audio read-only

  Transcribe audio to text with word-level timestamps. Converts spoken English audio into text with optional word-level timestamps and per-word confidence scores. Args: audio_base64: Base64-encoded audio data (WAV, MP3, OGG, FLAC, WebM). audio_format: Audio format hint. Auto-detected from magic bytes if omitted. include_timestamps: Whether to include word-level timing (default: true). Returns: dict with keys: - text (str): Full decoded transcript - words (list): Per-word results with timestamps, each containing: - word (str): The transcribed word - start (float): Start time in seconds - end (float): End time in seconds - confidence (float 0-1): Word-level confidence - audioDurationMs (int): Audio duration in milliseconds - metadata (dict): Processing time, audio length, model version - audioQuality (dict): Audio metrics (SNR, peak/RMS dB, etc.)

  Parameters:

  • audio_base64 (required) — string — Base64-encoded audio data. Supports WAV, MP3, OGG, FLAC, and WebM formats.
  • audio_format — Audio format hint — 'wav', 'mp3', 'ogg', 'flac', 'webm'. Auto-detected if omitted.
  • include_timestamps — boolean — If true, include word-level start/end times and confidence.

  Hints: read-only yes · destructive no · idempotent yes · open-world yes

• check_stt_service read-only

  Check if the speech-to-text service is healthy and ready. Returns: dict with keys: - status (str): 'healthy' or error state - modelLoaded (bool): Whether the STT model is loaded - version (str): API version

  Hints: read-only yes · destructive no · idempotent yes · open-world yes

• synthesize_speech read-only

  Generate natural speech audio from English text. Produces high-quality speech with 12 English voices. Returns base64-encoded WAV audio (16-bit PCM, 24kHz mono) along with metadata. Available voices: - af_heart (default), af_bella, af_nicole, af_sarah, af_sky (American female) - am_adam, am_michael (American male) - bf_emma, bf_isabella (British female) - bm_george, bm_lewis, bm_daniel (British male) Args: text: English text to synthesize (1-5000 characters). voice: Voice ID. See list above. Defaults to 'af_heart'. speed: Speed multiplier from 0.5 to 2.0 (default: 1.0). Returns: dict with keys: - audio_base64 (str): Base64-encoded WAV audio (16-bit PCM, 24kHz) - duration_ms (str): Audio duration in milliseconds - voice (str): Voice ID used - text_length (str): Input text character count - processing_ms (str): Synthesis time in milliseconds

  Parameters:

  • text (required) — string — English text to convert to speech. Max 5000 characters.
  • speed — number — Speech speed multiplier (0.5 = half speed, 2.0 = double).
  • voice — Voice ID (e.g. 'af_heart', 'am_adam'). Uses default if omitted.

  Hints: read-only yes · destructive no · idempotent yes · open-world yes

• list_tts_voices read-only

  List all available text-to-speech voices with metadata. Returns: dict with keys: - voices (list): Available voices, each with id, name, gender, accent, grade - defaultVoice (str): Default voice ID

  Hints: read-only yes · destructive no · idempotent yes · open-world yes

• check_tts_service read-only

  Check if the text-to-speech service is healthy and ready. Returns: dict with keys: - status (str): 'healthy' or error state - modelLoaded (bool): Whether the TTS model is loaded - version (str): API version

  Hints: read-only yes · destructive no · idempotent yes · open-world yes

• transcribe_audio_pro read-only

  Transcribe audio with Whisper Large V3 Turbo — multilingual STT. Supports 99 languages with automatic language detection, word-level timestamps, per-word confidence scores, and optional speaker diarization (identifies who spoke each word). Best-in-class WER (~2%). Args: audio_base64: Base64-encoded audio (WAV, MP3, OGG, FLAC, WebM). language: Language code. Auto-detected if omitted. Supports 99 languages. diarize: Enable speaker diarization (default: false). When true, each word includes a speaker label (e.g. SPEAKER_00, SPEAKER_01). Returns: dict with keys: - text (str): Full decoded transcript - words (list): Per-word results with timestamps, each containing: - word (str), start (float), end (float), confidence (float 0-1) - speaker (str|null): Speaker label when diarize=true - speakers (dict|null): Speaker info with count and labels - audioDurationMs (int): Audio duration in milliseconds - metadata (dict): Processing time, language, languageProbability - audioQuality (dict): Audio metrics (SNR, peak/RMS dB, etc.)

  Parameters:

  • audio_base64 (required) — string — Base64-encoded audio data. Supports WAV, MP3, OGG, FLAC, and WebM formats.
  • diarize — boolean — Enable speaker diarization to identify who spoke each word.
  • language — Language code (e.g. 'en', 'es', 'zh'). Auto-detected when omitted.

  Hints: read-only yes · destructive no · idempotent yes · open-world yes

• check_whisper_service read-only

  Check if the Whisper STT Pro service is healthy and ready. Returns: dict with keys: - status (str): 'healthy' or error state - modelLoaded (bool): Whether the Whisper model is loaded - diarizeLoaded (bool): Whether the diarization pipeline is loaded - version (str): API version - modelName (str): Whisper model name (e.g. 'large-v3-turbo')

  Hints: read-only yes · destructive no · idempotent yes · open-world yes

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