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1. What is AssemblyAI STT?

AssemblyAI Speech-to-Text (STT) is an advanced automatic speech recognition platform that uses AI to transcribe spoken English into text with high accuracy. AssemblyAI provides real-time streaming transcription with their Universal model. AssemblyAI is designed for enterprise-grade applications requiring accurate English transcription with features like speaker diarization, turn-based conversation management, and customizable confidence thresholds, making it ideal for voice agents, customer support systems, and conversational AI applications.

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2. Key Features of AssemblyAI STT

AssemblyAI offers comprehensive features for enterprise speech recognition:
  • Universal Model: High-accuracy English speech recognition model with enterprise-grade performance.
  • Real-Time Streaming: WebSocket-based streaming API with immutable transcripts and turn-based transcription for voice agent applications.
  • Speaker Diarization: Identify and separate different speakers in English audio streams.
  • Turn-Based Transcription: Provides speaking turns with unique identifiers, word-level metadata, and configurable silence detection.
  • High Accuracy: English transcription with enterprise-grade accuracy and low word error rates.
  • Format Flexibility: Supports PCM16 and Mu-law encoding with configurable sample rates for different telephony providers.
  • Enterprise Features: Batch and real-time processing, custom vocabulary, confidence scoring, and detailed analytics.

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3. How Bolna Uses AssemblyAI for STT

Bolna AI integrates AssemblyAI’s STT technology to enable accurate multilingual transcription for voice agents. Here’s how Bolna leverages AssemblyAI:
  • Real-Time Voice Processing: Bolna uses AssemblyAI’s streaming WebSocket API (v3) to convert spoken language into text in real time. The immutable transcript feature ensures stable text progression without overwrites.
  • English Voice Agent Support: Bolna voice agents use AssemblyAI’s streaming API for real-time English transcription with high accuracy and low latency.
  • Turn-Based Conversation Management: Bolna leverages AssemblyAI’s turn-based transcription to structure conversations, with each speaking turn having unique identifiers for better context management and response generation.
  • Telephony Provider Optimization: Bolna automatically configures audio encoding (Mu-law for Twilio, Linear16 for others) and sample rates (8kHz for telephony, 16kHz for web) based on the provider.
  • Streaming and Batch Processing: Bolna supports both real-time streaming for live conversations and batch processing for recorded calls, using AssemblyAI’s HTTP API for non-streaming scenarios.
  • Enterprise-Grade Reliability: Bolna uses AssemblyAI’s enterprise features including automatic language detection, confidence thresholds, and detailed latency tracking for production voice applications.

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4. List of AssemblyAI models supported on Bolna AI

Model
universal

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5. Supported Languages

For real-time voice agents, AssemblyAI streaming supports:
  • English - en

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Conclusion

AssemblyAI’s STT capabilities empower Bolna AI to deliver highly accurate, real-time English speech-to-text transcription for voice agents. By integrating AssemblyAI’s streaming technology, Bolna provides turn-based conversation management, immutable transcripts, and enterprise-grade reliability for production voice AI applications.