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Text to Speech

Generate natural-sounding speech from text, ready to save as a WAV file or play back in your app.

import ai.nobodywho.TextToSpeech
import java.io.File
import kotlinx.coroutines.runBlocking

fun main() = runBlocking {
    val tts = TextToSpeech.load(
        source = "hf://NobodyWho/Kokoro-82M", // Hugging Face repo (hf://owner/repo) or local folder with the model files.
        voice = "bf_emma", // Voice to use from the model.
        language = "en-gb", // Language code for the input text.
    )

    // Generate WAV bytes for this sentence.
    val wav = tts.synthesize(text = "Hello from NobodyWho!")
    // Save the audio to a file.
    File("out.wav").writeBytes(wav)
}

Models and sources​

NobodyWho supports three speech synthesis architectures, all in ONNX format:

source can be a Hugging Face repo (hf://owner/repo) as shown above, or a local directory laid out the same way as that repo. See Local model folder format and Architecture for setup details.

Kokoro​

For Kokoro, set voice and language together. They must agree with the model's available voices.

val tts = TextToSpeech.load(
    source = "hf://NobodyWho/Kokoro-82M",
    voice = "bf_emma",
    language = "en-gb",
)

Optional settings include:

  • voice: voice to use from the model, e.g. bf_emma. See the Kokoro voices folder for the full list. Defaults to bf_emma.
  • language: input language code. Supported values are listed on the Kokoro model page. Defaults to en-gb.
  • speed: speech speed multiplier. 1.0 is normal speed, lower values are slower, higher values are faster. Defaults to 1.0.

Supertonic​

For Supertonic, you can start with the default voice and language, or set them explicitly.

val tts = TextToSpeech.load(
    source = "hf://Supertone/supertonic-3",
    language = "en",
)

Optional settings include:

  • voice: voice style. Supported values are M1 to M5 and F1 to F5. Defaults to M1.
  • language: input language code. See the Supertonic model page for the full list. Defaults to en.
  • speed: speech speed multiplier. 1.0 is normal speed, lower values are slower, higher values are faster. Defaults to 1.05.
  • steps: denoising steps. Higher values can improve quality but are slower. Lower values are faster but can sound rougher. Must be greater than 0; defaults to 8.
  • silenceDuration: seconds of silence between long text chunks. Higher values add longer pauses. Must be 0 or higher; defaults to 0.3.

Pocket TTS​

For Pocket TTS, start with the default voice and language, or set them explicitly.

val tts = TextToSpeech.load(
    source = "hf://KevinAHM/pocket-tts-onnx",
    voice = "alba",
    language = "english_2026-04",
    huggingfaceToken = "hf_...", // Alternative: set the HF_TOKEN environment variable.
)

Optional settings include:

  • voice: built-in voice name. See the Pocket TTS voice catalogue. Defaults to alba.
  • language: language bundle name. See the available language bundles. Defaults to english_2026-04.
  • steps: quality steps. Higher values are slower. Defaults to 1.
  • precision: int8 for faster loading or fp32 for higher quality. Defaults to int8.
  • temperature: controls how varied the speech sounds. Defaults to 0.7.

Pocket TTS voice states are gated in kyutai/pocket-tts. Accept its terms, then pass a Hugging Face access token with huggingfaceToken, or alternatively set the HF_TOKEN environment variable.

Architecture​

architecture is the TextToSpeech model family behind a source. In most cases, you do not need to set it because NobodyWho can infer it by looking for "kokoro", "pocket-tts", or "supertonic" in the source string.

Set architecture when you use a local directory or a custom source that NobodyWho cannot recognize:

import ai.nobodywho.TextToSpeechArchitecture

val tts = TextToSpeech.load(
    source = "/path/to/local/kokoro-folder",
    architecture = TextToSpeechArchitecture.KOKORO,
)

Supported architecture values are TextToSpeechArchitecture.KOKORO and TextToSpeechArchitecture.SUPERTONIC.

GPU​

TextToSpeech uses GPU acceleration by default when available. Disable it with device = TextToSpeechDevice.CPU:

import ai.nobodywho.TextToSpeechDevice

val tts = TextToSpeech.load(
    source = "hf://Supertone/supertonic-3",
    device = TextToSpeechDevice.CPU,
)

Local model folder format​

When source is a local directory, point it at the top-level model folder and pass the matching architecture.

Use the Hugging Face file browsers as the reference layouts:

For Supertonic, that top-level folder must include both the onnx/ and voice_styles/ directories. Download the model files with the same relative paths, then pass that folder as source.