FAQ

Audio & speech

Speech recognition datasets

Paired audio and transcripts — with the sampling rate, accent and recording-condition checks that predict real performance.

ASR datasets are plentiful, and whether one transfers to your application depends on properties that are rarely in the headline description.

Four things to check before the hour count. Sampling rate, because a model trained at one rate degrades on another and telephone audio is narrowband. Recording conditions, because studio speech does not prepare a model for a noisy room or a car. Accent and dialect coverage, which in most corpora is narrower than the total hours imply. And transcription convention — whether disfluencies, numbers and punctuation are transcribed verbatim or normalised, which directly determines what your model outputs.

Read the recording setup section of the documentation. In this category it predicts deployed accuracy better than dataset size does, and it is the section most people skip.

Two spectrograms of the same five seconds of read English speech. The top one, sampled at 16 kHz, shows energy up to 8 kHz, including bursts of high-frequency energy from consonants; the bottom one, resampled to 8 kHz, shows the same pattern cut off flat at a dashed 4 kHz line, with nothing above it.
Telephone audio is narrowband in a literal sense: at an 8 kHz sampling rate everything above 4 kHz is gone, including much of what distinguishes consonants like s and f. A model trained only on clean 16 kHz recordings has never seen speech with that band missing, which is why the sampling rate is the first thing to check. Chart drawn by Dataset Finder from librosa/data · CC BY 4.0 (LibriSpeech audio) · Audio: LibriSpeech (Panayotov et al. 2015), read by Heather Barnett for LibriVox, CC BY 4.0
DatasetModalitySizeLicenceBest for
Common Voice - Audio corpus for speech recognitionAudio42,600 hoursCC0Robust ASR on diverse voice data
Medical Speech Transcription and Intent DatasetMultimodal8 hoursUnclear — see belowMedical speech recognition
OpenSLR Speech CorpusAudio3.3 GB recordingsCC BY-SA 4.0Speech recognition for low-resource languages
GigaSpeechAudio10,000 hoursResearch onlyLarge-scale English ASR
TED-LIUM DatasetAudio452 hoursCC BY-NC-ND 3.0Automatic transcription models
TIMIT DatasetAudio6,300 sentencesResearch onlyPhonetic and acoustic recognition
Google Speech CommandsAudio105,000 filesCC BY 4.0Lightweight keyword recognition
Licences in this shortlist — computed from the 7 datasets below. Red marks licences that are unclear or restricted; amber marks non-commercial, share-alike or mixed terms.
A line chart of mean WER (0 to 60%) across ten Spanish accents from Andean to Rioplatense for Alexa MX, Alexa ES, Alexa US, Whisper Base and Whisper Large-v2. Alexa lines sit between about 35 and 50%, Whisper Base around 18 to 27%, Whisper Large-v2 between about 6 and 10%.
Mean word error rate by Spanish regional accent on Common Voice recordings, for three Alexa language settings and two Whisper models. Whisper Large-v2 ranges from about 6% (Canary) to 10% (Caribbean), while every system has accents it handles worse than others. Check which accents a dataset covers, and report error rates per accent rather than one average. Image: Figure 7 of the article · CC BY 4.0 · from Nacimiento-García et al. 2024, Applied Sciences, “Gender and Accent Biases in AI-Based Tools for Spanish: A Comparative Study between Alexa and Whisper”, doi:10.3390/app14114734
№ 01

Common Voice - Audio corpus for speech recognition

Audio
Size
About 42,600 recorded hours (29,300 validated) of MP3 clips with TSV metadata, 295 languages, as of release 27.0 (data to September 2026)
Licence
CC0: Public Domain

A crowdsourced multilingual collection of spoken clips in MP3 with accompanying TSV metadata, each paired with its written text: about 42,600 recorded and 29,300 validated hours across 295 languages in release 27.0, now downloaded through the Mozilla Data Collective. Mozilla's contributor model gives it unusual demographic and accent breadth, and it is released into the public domain.

What to train on it

Training robust ASR on diverse voice data, evaluating speech recognition by demographic and linguistic criteria, and fine-tuning on specific voices or languages.

Source: innovatiana.com

№ 02

Medical Speech Transcription and Intent Dataset

Multimodal
Size
Over 8 hours of audio in WAV files, with associated transcripts in CSV and text format.
Licence
Terms not specified on the catalogue page beyond a pointer to Figure Eight (now Appen); check them before use

More than eight hours of WAV audio in which speakers describe common medical symptoms, paired with transcripts in CSV and plain text. Intent labels accompany the utterances, bridging speech recognition and clinical intent detection.

What to train on it

Training medical speech recognition, detecting symptoms and intent expressed aloud, and building health-specialised voice assistants.

Source: innovatiana.com

Diagram of the Whisper sequence-to-sequence speech recognition architecture.
Audio in, text out. Everything about your transcription convention — numbers, punctuation, disfluencies — becomes what the model emits. Image: openai/whisper · MIT repository
№ 03

OpenSLR Speech Corpus

Audio
Size
About 3.3 GB (compressed) of transcribed WAV recordings with TSV index tables; multi-speaker; 4 languages (af, st, tn, xh)
Licence
CC BY-SA 4.0 (Creative Commons Attribution-ShareAlike 4.0)

Transcribed WAV recordings with TSV index tables, from multiple speakers across four South African languages: Afrikaans, Sesotho, Setswana and Xhosa. OpenSLR publishes it as text-to-speech data (SLR32), so expect clean, consistent read speech rather than the varied conditions recognition needs; it is one of the few openly licensed resources for these low-resource languages.

What to train on it

Training speech recognition for low-resource languages, developing multilingual TTS systems, and validating multilingual audio pipelines.

Source: innovatiana.com

№ 04

GigaSpeech

Audio
Size
Up to 10,000 hours of transcribed audio, WAV/opus files, various audio segments
Licence
Apache 2.0 for metadata and code; the audio is gated and for non-commercial research and education only

Up to 10,000 hours of transcribed English speech in WAV and Opus, drawn from audiobooks, podcasts and YouTube. The mix of read and spontaneous speech across many topics makes it broader than audiobook-only corpora. Access is gated: SpeechColab does not own the audio copyright, so the audio is for non-commercial research and education only.

What to train on it

Training large-scale English ASR, building text-to-speech systems from varied audio, and evaluating models across topics and speaking styles.

Source: innovatiana.com

№ 05

TED-LIUM Dataset

Audio
Size
452 hours (release 3), NIST SPHERE audio with STM transcripts
Licence
CC BY-NC-ND 3.0 (non-commercial, no derivatives); talks and text remain the property of TED Conferences LLC

452 hours of TED talk recordings in release 3, as NIST SPHERE (.sph) audio with segment-aligned STM transcripts. The prepared-but-spoken register sits between audiobook reading and conversation; the licence is non-commercial and no-derivatives, and the talks remain TED's property.

What to train on it

Training automatic transcription models, generating multilingual subtitles, analysing spoken language style, and studying prosody and discourse markers.

Source: innovatiana.com

A vertical architecture diagram: a raw waveform feeds a Feature extractor box containing 'STFT + Filter banks' and two stride-2 downsampling CNNs; this feeds a Conformer Encoder Layer repeated x12 containing layer-norm feed-forward blocks, multi-head self-attention and a Conformer CNN module; outputs branch to an optional CTC loss and to an RNN-T section with Joiner, Predictor, Greedy Search for inference and RNN-T loss for training, ending in the output text 'THE BIRCH CANOE...'.
A speech stack from waveform through a Conformer encoder to CTC and RNN-T objectives. Both objectives learn your transcription convention exactly, punctuation, numbers and disfluencies included. Image: speechbrain/speechbrain · Apache-2.0 repository
№ 06

TIMIT Dataset

Audio
Size
6,300 recorded sentences, WAV (audio) and TXT (phonetic annotations) formats
Licence
Available under a specific license from the LDC (Linguistic Data Consortium), mainly for academic use

6,300 recorded American English sentences in WAV with detailed TXT phonetic annotations covering dialect variation. The phonetic transcription depth is its value; access goes through the Linguistic Data Consortium and is mainly academic.

What to train on it

Training phonetic and acoustic recognition, analysing American dialects, improving ASR, and studying regional pronunciation differences.

Source: innovatiana.com

№ 07

Google Speech Commands

Audio
Size
Approximately 105,000 audio files, WAV format
Licence
CC BY 4.0

About 105,000 one-second WAV clips of spoken keywords recorded by many speakers, built for low-latency on-device keyword spotting. The short uniform clips make it the standard benchmark for wake-word and voice-command models.

What to train on it

Training lightweight keyword recognition, developing voice interfaces for IoT and home automation, and analysing short audio signals.

Source: innovatiana.com

Screenshot of the Speech Data Explorer 'Global Statistics' page: 4.99 hours, 2703 utterances, vocabulary 8333 words, alphabet 28 chars, WER 3.82%, CER 1.16%; an Alphabet box listing space, apostrophe and the letters a to z; and a log-scale histogram of utterance durations from 0 to about 33 seconds, most between 2 and 15 seconds.
A speech corpus summarised in NVIDIA's Speech Data Explorer: five hours, 2,703 utterances and an alphabet of 28 characters, lower-case letters plus space and apostrophe. That line is the transcription convention made visible: a model trained on these transcripts will never write a digit or a comma. It and the clip-length histogram are worth a look before training. Image (cropped): NVIDIA/NeMo · Apache-2.0 repository

How this list was put together

Found by searching Dataset Finder for datasets whose documentation describes the task, then checked by hand. A keyword match is not a fit — the first pass picked up a coral survey for the depth-estimation list because it was recorded below fifty metres — so every entry was read against what this page covers, and the ones that matched a word without matching the task were removed.

Sizes and licences come from each dataset's own documentation, vague wording included. Where we found a re-upload or catalogue card stating a licence that the original release contradicts — a CC0 tag on Flickr photographs, MIT on data whose terms require a signed agreement — the entry gives the original terms and says so. The comparison table abbreviates licences; hover a cell for the full wording.

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