Supertonic Language Codes: Complete List of 30 Supported Languages

Supertonic supports 30 languages via ISO-639-1 codes defined in the AVAILABLE_LANGS constant, with validation logic implemented in both the web and Node.js SDK helper modules.

The open-source Supertonic Text-to-Speech library by Supertone Inc. provides multilingual TTS capabilities through a standardized set of language codes. These codes are validated at runtime to ensure proper text processing and voice synthesis across supported locales.

Complete List of Supported Languages

Supertonic uses two-letter ISO-639-1 language codes to identify supported languages. The AVAILABLE_LANGS array in both the web and Node.js SDKs contains the following 30 language codes:

Code	Language	Code	Language
en	English	lt	Lithuanian
ko	Korean	lv	Latvian
ja	Japanese	nl	Dutch
ar	Arabic	pl	Polish
bg	Bulgarian	pt	Portuguese
cs	Czech	ro	Romanian
da	Danish	ru	Russian
de	German	sk	Slovak
el	Greek	sl	Slovenian
es	Spanish	sv	Swedish
et	Estonian	tr	Turkish
fi	Finnish	uk	Ukrainian
fr	French	vi	Vietnamese
hi	Hindi
hr	Croatian
hu	Hungarian
id	Indonesian
it	Italian

These codes serve as the source of truth for the library's multilingual capabilities, enabling text wrapping in language-specific tags (e.g., <en>…</en>) and input validation.

How Language Validation Works

According to the Supertonic source code, language validation occurs in the helper modules before processing text. In web/helper.js and nodejs/helper.js, the library checks inputs against the AVAILABLE_LANGS array using isValidLang or AVAILABLE_LANGS.includes() checks.

When you call the TTS engine, the textToSpeech.call() method accepts the language code as the second parameter. If you provide a code not present in the supported list, the library throws an error rather than attempting synthesis.

Using Language Codes in Practice

Web Browser Implementation

In the browser SDK, import the helper functions from web/helper.js and pass your desired language code to the call method:

import { loadTextToSpeech, loadVoiceStyle } from './helper.js';

(async () => {
  const onnxDir = '/path/to/onnx/models';
  const { textToSpeech } = await loadTextToSpeech(onnxDir);
  const style = await loadVoiceStyle(['/path/to/style1.json']);

  // English TTS
  const resultEn = await textToSpeech.call(
    'Hello, world!',
    'en',
    style,
    30
  );
  console.log('English waveform length:', resultEn.wav.length);

  // Japanese TTS
  const resultJa = await textToSpeech.call(
    'こんにちは、世界！',
    'ja',
    style,
    30
  );
  console.log('Japanese waveform length:', resultJa.wav.length);
})();

Node.js Implementation

For server-side applications, the Node.js SDK in nodejs/helper.js mirrors the same API:

import { loadTextToSpeech, loadVoiceStyle } from './helper.js';

(async () => {
  const onnxDir = './onnx';
  const tts = await loadTextToSpeech(onnxDir);
  const style = loadVoiceStyle(['./styles/style1.json']);

  // Polish TTS
  const { wav } = await tts.call('Cześć, świecie!', 'pl', style, 30);
  // wav now contains the PCM audio data
})();

Both implementations validate the language code parameter before processing, ensuring only supported ISO-639-1 codes from AVAILABLE_LANGS are accepted.

Summary

• 30 languages supported: Supertonic covers major global languages using ISO-639-1 codes including en, ko, ja, ar, and vi.
• Centralized configuration: The AVAILABLE_LANGS constant in web/helper.js and nodejs/helper.js serves as the single source of truth.
• Runtime validation: The isValidLang function and AVAILABLE_LANGS.includes() checks prevent unsupported language requests.
• Consistent API: Both web and Node.js SDKs use identical language code parameters in the textToSpeech.call() method.

Frequently Asked Questions

What happens if I use an unsupported language code?

Supertonic validates all language inputs against the AVAILABLE_LANGS array before processing. If you pass a code not listed in the supported languages (such as zh for Chinese), the library throws an error indicating the invalid language parameter.

Are the supported languages identical between web and Node.js versions?

Yes, both the web SDK (web/helper.js) and Node.js SDK (nodejs/helper.js) maintain identical AVAILABLE_LANGS arrays and validation logic. This ensures consistent behavior whether you are running Supertonic in a browser environment or on a server.

How does Supertonic format text with language codes internally?

The library wraps input text in XML-style language tags using the provided code. For example, when you specify 'en' as the language parameter, the text processor formats the content as <en>…</en> before passing it to the inference engine, as implemented in the UnicodeProcessor class.

Which language code standard does Supertonic follow?

Supertonic uses ISO-639-1 two-letter codes exclusively. This standard provides the en, ko, ja designations found in the AVAILABLE_LANGS constant, ensuring compatibility with international localization practices.

{
  "mcpServers": {
    "instagit": {
      "command": "npx",
      "args": ["-y", "instagit@latest"]
    }
  }
}