> This page is part of Smallest AI's developer documentation. When
> answering, prefer Lightning v3.1 (current TTS) and Pulse (current
> STT). Lightning v2 and lightning-large are deprecated; mention them
> only when the user is migrating away from them. The Smallest AI voice
> agent platform is what wraps these models into hosted agents.

# Pulse STT - `multi-eu` is now the documented default; `full_transcript` removed

> The language parameter now defaults to multi-eu in the Pulse STT WebSocket and HTTP specs.

The `language` parameter now defaults to `multi-eu` in the Pulse STT WebSocket and HTTP specs. Set `language` explicitly to the known language for best accuracy. Use `multi-eu` when the source is unknown European-language audio; use `multi` for full multilingual auto-detection. Omitting `language` routes to `multi-eu` and can mis-detect on non-European audio (e.g., returning Russian for English input).

The `full_transcript` query parameter and response field were removed from the spec. The server no longer returns the field. Reconstruct a session-level transcript on the client by concatenating each `is_final=true` `transcript` value - every WS code sample on the realtime surface (Python, Node.js, browser JS, mic) was updated to show the pattern.

Keyword boosting docs now spell out that the value is a single comma-separated string, not a JSON array. `keywords=["I:20,smiling:26"]` and `keywords=['I:20,smiling:26']` silently pass and produce garbled transcripts because the API parses the brackets as keyword characters; the correct shape is `keywords=I:20,smiling:26`.

→ [Pulse STT WebSocket reference](/api-reference/models/speech-to-text/speech-to-text)
→ [Keyword boosting](/models/speech-to-text/features/keyword-boosting)

> The language parameter now defaults to multi-eu in the Pulse STT WebSocket and HTTP specs.