langlearn-tts
Provides text-to-speech synthesis via Amazon Polly with 100+ voices, 41 languages, and automatic engine selection (neural, standard, generative, long-form).
Provides high-quality text-to-speech synthesis with 70+ languages and over 5,000 voices, including voice settings and custom voice IDs.
Provides text-to-speech synthesis using OpenAI TTS models with 9 voices and 57 languages, supporting models tts-1 and tts-1-hd.
Click on "Deploy Server".
Wait a few minutes for the server to deploy. Once ready, it will show a "Started" state.
In the chat, type
@followed by the MCP server name and your instructions, e.g., "@langlearn-tts Pronounce 'bonjour' in French"
That's it! The server will respond to your query, and you can continue using it as needed.
Here is a step-by-step guide with screenshots.
langlearn-tts
A Claude Desktop extension that gives Claude the ability to speak. Ask Claude to pronounce words, generate audio flashcards, or run a full language lesson with audio — in 70+ languages.
Status (2026-02-21)
Core CLI and MCP surfaces are working with ElevenLabs, OpenAI TTS, and AWS Polly.
Provider defaults and audio variants (word + example) are still being standardized.
Claude Desktop directory submission is pending external review.
Related MCP server: elevenlabs-voice-mcp
Roadmap
See ROADMAP.md.
Quick Start
1. Get a TTS API key
You need an account with at least one text-to-speech provider:
ElevenLabs — best quality, 70+ languages, 5,000+ voices. Free tier: 10K chars/month. (Recommended)
OpenAI TTS — good quality, easiest setup, 57 languages, 9 voices.
AWS Polly — better quality, 41 languages, 100+ voices, difficult setup (setup guide).
2. Install in Claude Desktop
Download punt-langlearn-tts.mcpb and double-click to install. Claude Desktop will prompt you for your API key and an output directory.
3. Set up a tutor project (optional)
langlearn-tts ships with 28 tutor prompts — one for each combination of 7 languages and 4 levels. Setting up a project gives Claude a tutor persona that generates audio during lessons.
In Claude Desktop, click Projects in the sidebar
Click Create Project and name it (e.g., "German with Herr Schmidt")
Open the project, click Set custom instructions
Copy a prompt from the prompts directory and paste it into the Instructions field
Start a new conversation within that project
Language | High School | 1st Year | 2nd Year | Advanced |
German | Herr Schmidt | Professorin Weber | Professor Hartmann | Professor Becker |
Spanish | Profesora Elena | Profesor Garcia | Profesora Carmen | Profesora Reyes |
French | Madame Moreau | Professeur Laurent | Professeur Dubois | Professeur Beaumont |
Russian | Irina Petrovna | Professor Dmitri | Professor Natasha | Professor Mikhail |
Korean | Kim-seonsaengnim | Professor Park | Professor Kim | Professor Yoon |
Japanese | Tanaka-sensei | Yamamoto-sensei | Suzuki-sensei | Mori-sensei |
Chinese | Laoshi Wang | Professor Chen | Professor Zhang | Professor Wei |
Each prompt is calibrated to the student's level, based on Mollick & Mollick's "Assigning AI" framework.
4. Try it out
In any Claude Desktop conversation, try:
"Say 'Guten Morgen' in German"
"Create an audio flashcard: 'good morning' in English, then 'Guten Morgen' in German"
"Synthesize these Spanish words as a merged audio file: hola, gracias, por favor, de nada"
"Generate pair flashcards for these German vocabulary words: strong/stark, house/Haus, book/Buch"
Audio plays automatically after each request. Files are saved to your output directory (~/langlearn-audio by default).
Features
Pronounce anything — ask Claude to say a word or phrase and hear it spoken aloud
Audio flashcards — Claude creates an MP3 with English first, then the target language, with a pause between them
Vocabulary lists — give Claude a list of words and get back individual or merged audio files
70+ languages — German, Spanish, French, Russian, Korean, Japanese, Chinese, and many more
Tutor mode — 28 built-in tutor personas that teach with audio throughout the lesson
Multiple voices — each provider offers a range of voices; ask Claude to use a specific one by name
Adjustable speed — audio defaults to 90% speed so learners can hear pronunciation clearly
Troubleshooting
If something isn't working, ask Claude to run a health check:
"Run the doctor command to check if everything is set up correctly"
Logs are written to ~/.langlearn-tts/logs/langlearn-tts.log (never contains the text you synthesize). See PRIVACY.md for details.
Developer Reference
Everything below is for developers using the CLI, integrating with other MCP clients, or contributing to the project.
Claude Code / CLI
curl -fsSL https://raw.githubusercontent.com/punt-labs/langlearn-tts/14f4194/install.sh | shThe default provider is AWS Polly. To use a different provider:
LANGLEARN_TTS_PROVIDER=elevenlabs curl -fsSL https://raw.githubusercontent.com/punt-labs/langlearn-tts/14f4194/install.sh | shuv tool install punt-langlearn-tts
langlearn-tts install --provider polly
langlearn-tts doctorcurl -fsSL https://raw.githubusercontent.com/punt-labs/langlearn-tts/14f4194/install.sh -o install.sh
shasum -a 256 install.sh
cat install.sh
sh install.shInstall ffmpeg for audio stitching (pairs, merged batches):
# macOS (requires Homebrew — install from https://brew.sh if needed)
brew install ffmpeg
# Linux — see https://ffmpeg.org/download.html for your distro
# Windows
winget install --id Gyan.FFmpegClaude Desktop setup via CLI
langlearn-tts installWrites to ~/Library/Application Support/Claude/claude_desktop_config.json (macOS). Options: --provider NAME, --output-dir PATH, --uvx-path PATH. Restart Claude Desktop after running.
Or add manually:
{
"mcpServers": {
"langlearn-tts": {
"command": "/absolute/path/to/uvx",
"args": ["--from", "punt-langlearn-tts", "langlearn-tts-server"],
"env": {
"LANGLEARN_TTS_OUTPUT_DIR": "/absolute/path/to/output/directory"
}
}
}
}Claude Desktop does not inherit your shell environment. API keys must be literal values (env var references are not supported). Restart after editing.
Environment variables
Env var | Required | Description |
| No |
|
| For ElevenLabs | Your API key |
| For OpenAI | Your API key |
| No | Output directory (default: |
| No | Model name. ElevenLabs: |
For Polly, AWS credentials are read from ~/.aws/credentials.
CLI Usage
# Single synthesis
langlearn-tts synthesize "Guten Morgen" --voice daniel -o morning.mp3
# Custom speech rate (percentage, default 90)
langlearn-tts synthesize "Привет" --voice tatyana --rate 70 -o privet.mp3
# ElevenLabs with voice settings
langlearn-tts synthesize "Guten Morgen" --voice Rachel \
--stability 0.5 --similarity 0.7 --style 0.3 --speaker-boost
# Pair: English + German stitched with a pause
langlearn-tts synthesize-pair "good morning" "Guten Morgen" \
--voice1 joanna --voice2 daniel -o pair.mp3
# Batch from JSON file (["hello", "world", "good morning"])
langlearn-tts synthesize-batch words.json -d output/
# Batch merged into single file
langlearn-tts synthesize-batch words.json -d output/ --merge --pause 800
# Pair batch from JSON file ([["strong", "stark"], ["house", "Haus"]])
langlearn-tts synthesize-pair-batch pairs.json -d output/
# Browse AI tutor prompts
langlearn-tts prompt list
langlearn-tts prompt show german-high-school | pbcopyVoices
ElevenLabs — 5,000+ voices. Any voice works with any language. You can also pass a voice ID directly (the 20-character string from the ElevenLabs dashboard). Voice settings: --stability, --similarity, --style (0.0–1.0), --speaker-boost (flag).
AWS Polly — 93 voices from the AWS Polly voice list. Each voice is trained for a specific language. Engine (neural, standard, generative, long-form) is selected automatically.
OpenAI TTS — 9 voices: alloy, ash, coral, echo, fable, onyx, nova, sage, shimmer. Default model: tts-1. Use --model tts-1-hd for higher quality.
All voice names are case-insensitive.
MCP Tools
Tool | Description |
| Single text to MP3 |
| Multiple texts, optionally merged |
| Two texts stitched with a pause |
| Multiple pairs, optionally merged |
Each tool accepts auto_play (default: true) to play audio immediately after synthesis.
Other MCP clients
langlearn-tts works with any MCP client that supports stdio transport. Use the server command uvx --from punt-langlearn-tts langlearn-tts-server with the environment variables above. Find your uvx path with which uvx — all paths must be absolute.
Development
git clone https://github.com/punt-labs/langlearn-tts.git
cd langlearn-tts
uv sync --all-extras
uv run pytest tests/ -v
uv run ruff check src/ tests/
uv run ruff format src/ tests/
uv run mypy src/ tests/
uv run pyright src/ tests/License
MIT
Available Tools
4 toolssynthesizeA
Synthesize text to an MP3 audio file.
Args: text: The text to convert to speech. With ElevenLabs eleven_v3, you can embed audio tags in square brackets anywhere in the text to control delivery — e.g. [tired], [excited], [whisper], [sad], [sigh], [laughs], [dramatic tone]. Tags are free-form; the model interprets them as performance cues. Combine with punctuation (ellipsis for pauses, ! for emphasis) for best results. Tags only work with ElevenLabs eleven_v3 model. voice: Voice name. Default: provider's default voice (currently matilda for ElevenLabs, joanna for Polly, nova for OpenAI). If language is provided without voice, a suitable default voice for that language is selected automatically. language: ISO 639-1 language code (e.g. 'de', 'ko', 'fr'). Enables language-aware voice selection and validation. With Polly, validates voice-language compatibility. With ElevenLabs/OpenAI, passed through (voices are multilingual). rate: Speech rate as percentage (90 = 90% speed, good for language learners). Defaults to 90. ElevenLabs ignores rate; use audio tags like [rushed] or [drawn out] instead. auto_play: Open the file in the default audio player after synthesis. Defaults to true. output_path: Full path for the output file. If not provided, a file is auto-generated in output_dir. output_dir: Directory for output. Defaults to TTS_OUTPUT_DIR env var or ~/langlearn-audio/. stability: ElevenLabs voice stability (0.0-1.0). Ignored by other providers. Defaults to provider default. similarity: ElevenLabs voice similarity boost (0.0-1.0). Ignored by other providers. Defaults to provider default. style: ElevenLabs voice style/expressiveness (0.0-1.0). Ignored by other providers. Defaults to provider default. speaker_boost: ElevenLabs speaker boost toggle. Ignored by other providers. Defaults to provider default.
Returns: JSON string with path, text, voice, and language fields.
Inputs: text (required), rate, style, voice, +7 more. Returns: result
synthesize_batchA
Synthesize multiple texts to MP3 files.
Args: texts: List of texts to synthesize. With ElevenLabs eleven_v3, embed audio tags like [tired], [excited], [whisper] in text. voice: Voice name for all texts. Default: provider's default voice (currently matilda for ElevenLabs, joanna for Polly, nova for OpenAI). If language is provided without voice, auto-selects. language: ISO 639-1 language code (e.g. 'de', 'ko'). rate: Speech rate as percentage. Defaults to 90. merge: If true, produce one merged file instead of separate files per text. Defaults to false. pause_ms: Pause between segments in milliseconds when merging. Defaults to 500. auto_play: Open the file(s) in the default audio player after synthesis. Defaults to true. output_dir: Directory for output files. Defaults to TTS_OUTPUT_DIR env var or ~/langlearn-audio/. stability: ElevenLabs voice stability (0.0-1.0). similarity: ElevenLabs voice similarity boost (0.0-1.0). style: ElevenLabs voice style/expressiveness (0.0-1.0). speaker_boost: ElevenLabs speaker boost toggle.
Returns: JSON string with list of results, each containing path, text, voice, and language fields.
Inputs: texts (required), rate, merge, style, +8 more. Returns: result
synthesize_pairA
Synthesize a pair of texts and stitch them into one MP3.
Creates [text1 audio] [pause] [text2 audio]. Use for language learning pairs like "strong" (English) + "stark" (German).
Args: text1: First text (typically English). With ElevenLabs eleven_v3, embed audio tags like [tired], [excited], [whisper] in text. text2: Second text (typically target language). Same audio tag support as text1. voice1: Voice for text1. Defaults to provider's default voice. If lang1 is provided without voice1, auto-selects. voice2: Voice for text2. Defaults to provider's default voice. If lang2 is provided without voice2, auto-selects. lang1: ISO 639-1 language code for text1 (e.g. 'en'). lang2: ISO 639-1 language code for text2 (e.g. 'de'). rate: Speech rate as percentage. Defaults to 90. pause_ms: Pause between the two texts in milliseconds. Defaults to 500. auto_play: Play the audio after synthesis. Defaults to true. output_path: Full path for the output file. output_dir: Directory for output. Defaults to TTS_OUTPUT_DIR env var or ~/langlearn-audio/. stability: ElevenLabs voice stability (0.0-1.0). similarity: ElevenLabs voice similarity boost (0.0-1.0). style: ElevenLabs voice style/expressiveness (0.0-1.0). speaker_boost: ElevenLabs speaker boost toggle.
Returns: JSON string with path, text, voice, and language fields.
Inputs: text1 (required), text2 (required), rate, lang1, +11 more. Returns: result
synthesize_pair_batchA
Synthesize multiple text pairs and stitch each into MP3 files.
Each pair becomes [text1 audio] [pause] [text2 audio]. Use for vocabulary lists like [["strong","stark"], ["house","Haus"]].
Args: pairs: List of [text1, text2] pairs. With ElevenLabs eleven_v3, texts can include audio tags like [tired], [excited]. voice1: Voice for all first texts. Defaults to provider's default. If lang1 is provided without voice1, auto-selects. voice2: Voice for all second texts. Defaults to provider's default. If lang2 is provided without voice2, auto-selects. lang1: ISO 639-1 language code for first texts (e.g. 'en'). lang2: ISO 639-1 language code for second texts (e.g. 'de'). rate: Speech rate as percentage. Defaults to 90. pause_ms: Pause between pair segments in milliseconds. Defaults to 500. merge: If true, produce one merged file instead of separate files per pair. Defaults to false. auto_play: Play the audio after synthesis. Defaults to true. output_dir: Directory for output files. Defaults to TTS_OUTPUT_DIR env var or ~/langlearn-audio/. stability: ElevenLabs voice stability (0.0-1.0). similarity: ElevenLabs voice similarity boost (0.0-1.0). style: ElevenLabs voice style/expressiveness (0.0-1.0). speaker_boost: ElevenLabs speaker boost toggle.
Returns: JSON string with list of results.
Inputs: pairs (required), rate, lang1, lang2, +10 more. Returns: result
Tool Schema Changelog
Recent tool additions, removals, and schema changes observed during successful MCP inspections.
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TDQS
Scored across 4 tools
Each tool has a clearly distinct purpose: single text, batch texts, a single pair, and multiple pairs. The descriptions explicitly differentiate use cases, making confusion unlikely.
All tools follow the same verb-based pattern, starting with 'synthesize' and adding descriptive suffixes (batch, pair, pair_batch). The naming is fully consistent and predictable.
Four tools provide a focused yet complete range of synthesis options, from single to batch to pair-based. This is well-scoped for a TTS server without being bloated.
The toolset covers single, batch, pair, and pair-batch synthesis comprehensively. The only notable omission is a way to discover available voices or languages without synthesizing, which would aid agents in choosing parameters.
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