> For clean Markdown of any page, append .md to the page URL.
> For a complete documentation index, see https://docs.vapi.ai/llms.txt.
> For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://docs.vapi.ai/_mcp/server.

# Enhanced Transcription Features & Speech Processing

1. **Gladia Transcription Enhancements**: Improve transcription accuracy and performance with new [`GladiaTranscriber`](https://api.vapi.ai/api#:~:text=GladiaTranscriber) features:
   * `region`: Choose between `us-west` and `eu-west` for optimal latency and data residency compliance
   * `receivePartialTranscripts`: Enable low-latency streaming transcription for real-time conversation flow
   * Enhanced language detection with support for both single and multiple language modes

2. **Advanced Deepgram Controls**: Fine-tune speech recognition with enhanced [`DeepgramTranscriber`](https://api.vapi.ai/api#:~:text=DeepgramTranscriber) settings:
   * `eotThreshold`: End-of-turn detection threshold for precise conversation boundaries (e.g., 0.7)
   * `eotTimeoutMs`: Maximum wait time for end-of-turn detection in milliseconds (e.g., 5000ms)
   * `eagerEotThreshold`: Early end-of-turn detection for responsive conversations (e.g., 0.3)

3. **AssemblyAI Keyterms Enhancement**: Boost recognition accuracy for critical terms with [`AssemblyAITranscriber.keytermsPrompt`](https://api.vapi.ai/api#:~:text=AssemblyAITranscriber.keytermsPrompt):
   * Support for up to 100 keyterms, each up to 50 characters
   * Improved recognition for specific words and phrases
   * Additional cost: \$0.04/hour when enabled

4. **Speechmatics Custom Vocabulary**: Enhance recognition accuracy with [`SpeechmaticsCustomVocabularyItem`](https://api.vapi.ai/api#:~:text=SpeechmaticsCustomVocabularyItem):
   * `content`: The word or phrase to add (e.g., "Speechmatics")
   * `soundsLike`: Alternative phonetic representations (e.g., \["speech mattix"]) for better pronunciation handling

5. **Word-Level Confidence**: Access detailed transcription confidence data with [`CustomLLMModel.wordLevelConfidenceEnabled`](https://api.vapi.ai/api#:~:text=CustomLLMModel.wordLevelConfidenceEnabled), providing word-by-word accuracy metrics for quality assessment and debugging.

6. **Enhanced Message Metadata**: Store transcription confidence and other metadata in [`UserMessage.metadata`](https://api.vapi.ai/api#:~:text=UserMessage.metadata), enabling detailed analysis of transcription quality and user speech patterns.

> **Warning**
>
> `AssemblyAITranscriber.wordFinalizationMaxWaitTime` is now deprecated. Use the new smart endpointing plans for better speech timing control. The deprecated property will be removed in a future release.

## Transcription Improvements

#### Regional Processing

Choose optimal transcription regions with Gladia's `us-west` and `eu-west` options for reduced latency and compliance.

#### Real-Time Streaming

Enable partial transcripts for immediate response processing, reducing perceived latency in conversations.

#### Advanced Speech Detection

Fine-tune end-of-turn detection with configurable thresholds and timeouts for natural conversation flow.

#### Custom Vocabulary

Improve accuracy for domain-specific terms, company names, and technical jargon with enhanced vocabulary support.