SPeech & Audio

Multi-Speaker Audio Transcription

Accurate multi-speaker audio transcription at scale, speaker diarization, 99.5% accuracy, and 165,000+ hours of audio across languages and acoustic environments.

Transcribing a single clear speaker in a quiet environment is a solved problem. Transcribing overlapping speech, accented voices, cross-talk, and background noise at scale with 99.5% accuracy is not. Appen's audio transcription service delivers production-grade multi-speaker transcription across the acoustic conditions, language varieties, and specialised domains that commodity transcription services fail on.

165,000+ hours of transcribed audio across 100 languages. 99.5% accuracy on domain-specific content. Built for AI training data, not human reading.

What Appen Delivers

Speaker Diarisation and Labeling

Accurate attribution of each utterance to its speaker across multi-party conversations, meetings, interviews, and call recordings. Diarisation quality is the foundation of any downstream analysis that requires knowing who said what, and Appen's human-in-the-loop diarisation consistently outperforms purely automated systems on overlapping speech and similar-sounding speakers.

Verbatim and Normalised Transcription

Choice of verbatim transcription preserving disfluencies, false starts, and non-standard pronunciations, or normalised transcription cleaned to standard orthographic conventions, depending on your training data requirements. Both formats are available with speaker labels and optional timestamp alignment.

Domain-Specific Terminology Accuracy

Specialist transcription for medical, legal, financial, and technical content domains where accurate terminology is not optional. Domain-specific transcribers are selected and tested for subject-matter comprehension, not just transcription speed.

Noisy and Adverse Condition Audio

Transcription of recordings with background noise, compression artifacts, telephony degradation, and multi-channel audio quality issues. Appen's quality processes include audio preprocessing assessment and transcriber training on the specific acoustic challenges present in your dataset.

Transcription as the Foundation of Speech AI

Automatic speech recognition models, speaker verification systems, and conversational AI platforms all train on transcribed audio. The accuracy, consistency, and domain coverage of that transcription determines the ceiling of what the model can learn. Appen's transcription programmes are designed for AI training requirements, not just readability.

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Talk to our team about speech and audio data solutions, from expressive TTS synthesis to dialectal speech collection across low-resource languages.

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