piper-phonemize

Phonemization library for Piper text-to-speech, compiled to WebAssembly.

This package converts text to IPA phonemes using espeak-ng, running entirely in Node.js without any native dependencies.

espeak-ng-data is bundled in this package — no need to download it separately!

Installation

npm install piper-phonemize

Quick Start

const piperPhonemize = require('piper-phonemize');

// That's it! espeak-ng-data is bundled and auto-initialized on first use.
const result = piperPhonemize.phonemizeToString('Hello world', 'en-us');
console.log(result); // ['həlˈoʊ wˈɜːld']

API Reference

initialize(dataDir?)

Initialize espeak-ng with the given data directory. Optional — called automatically on first use with bundled data.

• dataDir (string, optional): Path to espeak-ng-data directory. If omitted, uses bundled data.
• Returns: Sample rate (22050) on success, -1 on failure

phonemize(text, voice)

Phonemize text and return raw phoneme code points.

• text (string): Text to phonemize
• voice (string, optional): espeak-ng voice (e.g., 'en-us', 'de', 'fr'). Default: 'en-us'
• Returns: Array of sentences, each containing an array of uint32 code points, or null on failure

phonemizeToString(text, voice)

Phonemize text and return IPA strings.

• text (string): Text to phonemize
• voice (string, optional): espeak-ng voice. Default: 'en-us'
• Returns: Array of IPA strings, or null on failure

version

The version of piper-phonemize (string).

Supported Languages

espeak-ng supports many languages including:

• English (en-us, en)
• German (de)
• French (fr)
• Spanish (es)
• Italian (it)
• Portuguese (pt)
• Russian (ru)
• Chinese (zh)
• Japanese (ja)
• Korean (ko)
• And many more...

Example

const piperPhonemize = require('piper-phonemize');

// No initialization needed — espeak-ng-data is bundled!

// Phonemize different languages
const examples = [
  { text: 'Hello world', voice: 'en-us' },
  { text: 'Hallo Welt', voice: 'de' },
  { text: 'Bonjour le monde', voice: 'fr' },
  { text: 'Hola mundo', voice: 'es' },
];

for (const { text, voice } of examples) {
  const result = piperPhonemize.phonemizeToString(text, voice);
  console.log(`${voice}: ${result[0]}`);
}

// Get raw code points
const phonemes = piperPhonemize.phonemize('Hello', 'en-us');
console.log('Code points:', phonemes[0]);
console.log('IPA:', String.fromCodePoint(...phonemes[0]));

License

GPL-3.0-or-later (due to espeak-ng dependency)

Links

• GitHub Repository
• Piper TTS
• espeak-ng