> ## Documentation Index
> Fetch the complete documentation index at: https://docs.inworld.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Release Notes

> Product updates and improvements to TTS

<Update label="May 5, 2026">
  ## Realtime TTS-2

  Launched [Realtime TTS-2](https://inworld.ai/blog/realtime-tts-2) (`inworld-tts-2`), our most powerful and expressive TTS model:

  * **Natural Language Steering:** Direct any voice with bracketed instructions like `[say excitedly]`, `[whisper in a hushed style]`, or free-form directions like `[speak as if barely holding back rage]`. Covers articulation, intonation, volume, pitch, range, speed, vocal style, and non-verbals (`[laugh]`, `[sigh]`, etc.). See the [Steering](/tts/capabilities/steering) guide.
  * **Stronger Multilingual Support:** Production-quality synthesis across 15 languages, plus experimental support for 90+ additional languages. See [Languages](/tts/capabilities/multilingual).
  * **Cross-Lingual Voice Synthesis:** Reuse the same voice across multiple languages. For best results, specify the [`language`](/api-reference/ttsAPI/texttospeech/synthesize-speech#body-language) field.
  * **Voice Localization:** Localize your voice for the most consistent, native-sounding speech in a target language. See [Voice Localization](/tts/capabilities/multilingual#voice-localization).
  * **Delivery Mode:** New [`deliveryMode`](/api-reference/ttsAPI/texttospeech/synthesize-speech#body-delivery-mode) field (`STABLE`, `BALANCED`, `CREATIVE`) controls the trade-off between consistency and emotional range.
  * **Updated Voice Design:** Released an updated version of Voice Design with improved generations. See [Voice Design](/tts/voice-design).
</Update>

<Update label="January 21, 2026">
  ## Inworld TTS 1.5

  Launched [Inworld TTS 1.5](https://inworld.ai/blog/introducing-inworld-tts-1-5), our newest generation of realtime TTS models featuring:

  * **Two New Models:** Our flagship model `inworld-tts-1.5-max` is ideal for most use cases, with the best balance of quality and speed. For use cases where latency is the top priority, we also offer `inworld-tts-1.5-mini`.
  * **Latency Improvements:** Our new TTS-1.5 models achieve P90 latency for first audio chunk delivery under 250ms for our Max model and under 130ms for our Mini model, a 4x improvement compared to TTS-1.
  * **More Expressive and More Stable:** TTS-1.5 is 30% more expressive than prior generations and demonstrates a 40% reduction in word error rates.
  * **Additional Languages:** We've added support for additional languages, including Hindi, Arabic, and Hebrew, bringing total languages supported to 15.
</Update>

<Update label="August 22, 2025">
  ## Updates to Inworld TTS

  Released an upgraded version of the Inworld TTS models with higher overall quality.

  * **Speech Quality:** Clearer, more natural speech with smoother pacing and more accurate pronunciation.
  * **Voice Similarity:** Cloned voices sound closer to the originals, preserving each voice’s unique style.
  * **Non-English Languages:** More consistent, reliable output across supported non-English languages.
  * **Custom Pronunciation:** New support for inline IPA, giving you control over exact word pronunciations. See the [Key Features](/tts/capabilities/custom-pronunciation) for details.
</Update>