Language Support
SpeechifyAI Build models support synthesizing speech in multiple languages. The API handles both single-language texts and mixed-language inputs.
Non-English synthesis requires simba-3.0, or simba-multilingual on a workspace pinned to an API version before 2026-09-21, after which it is served by our current multilingual model. simba-3.2 and simba-english are English-only; a non-English voice on them returns 400.
Which model covers which languages
Simba 3.0 languages
simba-3.0 is streaming-native and officially supports six languages across these seven locales:
es-ES and es-MX voices are interchangeable on simba-3.0: pass language: es-ES with an es-MX-labeled voice (or the reverse) and synthesis works either way.
You select the language with the language request parameter; when you omit it, the model is chosen from the voice’s own locale. simba-3.0 routes English to its English training and everything else to its multilingual one, so this is an internal detail: the model ID you pass never changes.
Languages outside this list often still produce usable audio on simba-3.0, but they are not validated or officially supported. simba-multilingual covers the full locale set below, on a workspace pinned to an API version before 2026-09-21, after which it is served by our current multilingual model.
Fully Supported Languages
The following table describes the legacy simba-multilingual model, not Simba 3.0. It requires an API version pinned before 2026-09-21; from 2026-11-21, that ID is served by our current multilingual model. For current integrations, use the Simba 3.0 languages above.
Beta Languages
These are the beta languages of the legacy simba-multilingual model. They are not a list of supported Simba 3.0 languages. The same retirement (2026-09-21) and replacement-training (2026-11-21) dates apply.
Coming Soon
We will soon support these additional languages:
Using the language Parameter
Our speech synthesis endpoints (/v1/audio/speech and
/v1/audio/stream) support the optional language
parameter, which should follow the locale naming standard (e.g., en-US,
fr-FR).
When to specify the language:
- Known single language: If you know the input text is entirely in one language, providing the
languageparameter will result in better audio quality. - Unknown or mixed language: If you’re unsure of the input language or the text contains multiple languages, omit the
languageparameter. Speechify models will automatically detect and handle the language(s) in the input.
Voice Cloning Languages
Both Simba 3 models support voice cloning on paid plans. A cloned voice can synthesize in the selected model’s supported languages: English on Simba 3.2, or the six languages above on Simba 3.0. Check voice and model compatibility before sending a request. See Voice Cloning for sample requirements and implementation details.