English speech dataset, roughly 500 hours ready to license
Our OTS English speech dataset is roughly 500 hours of English speech, prompts and conversations, already recorded by English speakers in our 30,000+ network, with consent from every speaker for commercial AI training. License it now and train your English speech recognition model without waiting on a new collection.
- ~500 h of English in stock
- ~35,000 h across the OTS pool
- 100% of speakers consented
- ISO 27001 certified
- SOC 2 report under NDA
- GDPR DPAs and HIPAA BAAs on request
What's in the English speech dataset?
The IndecalAI OTS English speech dataset is roughly 500 hours of English speech, prompts and conversations, recorded by English speakers in our network who all consented to commercial AI training. It's already recorded, so you can license it now instead of waiting on a new collection.
English is the default first language for most voice products, and the one many speech models are tested on before any other. Even so, a model that works for one accent can stumble on another, so English speech from a wide range of speakers is still worth licensing.
Every recording comes with a transcript and metadata about the speaker, the device and the setting, and you can take it as WAV, OGG or another common format. Every order starts with sample clips and a spec sheet, so you can match the data against your model before you agree a licence.
Need more than what's in stock? English speakers from our 30,000+ network record new speech to your brief, and our English data page covers what we collect to order.
English speech dataset at a glance
- Hours
- Roughly 500 hours, already recorded
- Language
- English, en
- Content
- Speech, prompts and conversations
- Consent
- Every speaker consented to commercial AI training
- Speakers
- English speakers from our 30,000+ network
- Audio and transcripts
- Transcripts and metadata with every recording, in WAV, OGG and more
- Licence
- Terms agreed with each customer, in writing
- Price
- Quoted per order
- Samples
- English sample clips sent in reply to your request
- Security
- ISO 27001 certified. SOC 2 report available under NDA. GDPR DPAs and HIPAA BAAs on request.
What comes with every English recording
Recorded on the devices and in the places your users actually speak, and delivered in the format your pipeline expects.
| Detail | In the English dataset |
|---|---|
| Speech types | A mix of scripted prompts and natural conversations |
| Recording devices | Mobile phones, laptops and studio microphones |
| Environments | Quiet rooms and noisy, everyday settings |
| Transcripts | Included with every recording |
| Speaker metadata | Speaker details, such as gender and age, for each recording |
| Recording metadata | The device and the setting for each recording |
| Audio formats | WAV, OGG and other common formats |
| Sample rates | Listed for each recording on the spec sheet |
What roughly 500 hours of English speech looks like
Roughly 500 hours sounds abstract until you play it: about 21 days of English speech without a pause. That's why we send sample clips and a spec sheet first, so you can judge the whole from a part.
- ~500 hours of English speech
- ~30,000 minutes
- ~1.8M seconds of audio
- ~21 days, played back to back
Hours here are recorded audio. When you compare quotes, check whether each one counts audio hours or only the parts where someone is talking.
English at a glance, for speech teams
The facts that shape an English speech project, from who speaks it to how it's written. Our English data page covers what we collect to order.
Speakers
~1.5 billion
people speak English as a first or second language, about 372 million of them natively (Ethnologue, 2026).
Where it's spoken
Worldwide
A first language in the US, UK, Canada, Australia and beyond, and a second language across India, Africa, Europe and Asia.
Script
Latin alphabet
Written left to right, with spelling that often doesn't match how words sound.
Family
Germanic
A Germanic language with a large share of words borrowed from French and Latin.
Varieties
Many Englishes
American, British, Indian, Nigerian, Australian and other Englishes differ in sounds, words and rhythm.
Codes
en · eng
ISO 639-1 and ISO 639-3 codes. Locales speech APIs often use: en-US, en-GB, en-IN.
English speech dataset, voice dataset or speech corpus?
Speech dataset, voice dataset, corpus: the names overlap. Here's how they differ, and where our English data sits.
English speech dataset
The general term
Recorded English speech with details about each recording, for training and testing speech models. The name this page uses.
English voice dataset
Usually the same thing
Some teams mean voice for text-to-speech or speaker recognition, which needs cleaner audio. Part of our data was recorded in a studio, so ask for those recordings.
English audio dataset
A wider term
It can include music or background sound. Ours is speech audio: English speech, prompts and conversations.
English speech corpus
The research name
A structured collection of recordings and their details. Commercial datasets are corpora too, licensed instead of published.
English ASR or speech-to-text dataset
Speech plus what was said
For training a model that turns English audio into text. Every recording in our English dataset comes with a transcript.
Accented English speech data
English as people speak it
Speech from non-native and regional speakers, which many voice products need most. Ask which accents are in the hours you license.
What makes English hard for speech recognition
Where English speech recognition usually goes wrong, and how to spot it in a sample before you buy.
Fillers, restarts and casual speech
Real English speech is full of um, like, restarts and words run together, like gonna and wanna. A model trained only on read text stumbles on how people actually talk, so listen for natural speech in a sample.
Spelling doesn't follow sound
The same sound can be spelled many ways in English, and the same spelling said many ways. Transcripts need one consistent style for names, numbers and filler words, so check how the samples handle them.
Accents across the world
An American, British, Indian or Nigerian speaker can say the same sentence very differently. Check that the speaker mix covers the accents your users have.
Numbers and names
Amounts, dates, phone numbers and names are said in many ways, like twenty twenty-six or two thousand twenty-six. The audio and the transcript have to agree on how these are written.
What teams build with an English speech dataset
The projects English speech data usually ends up in. They describe the work, not who it was for.
English speech recognition
Train or fine-tune an English speech-to-text model, or adapt a multilingual model so it handles English well.
Voice bots and IVR
Teach a voice bot how English callers actually ask for things, in the words and accents they use.
Customer service calls
English speech for models that route, transcribe or summarize customer calls about accounts, orders and claims.
Voice in the car and at home
An English base for in-car assistants and smart devices, before recording commands in the real setting.
Support and speech analytics
English conversations for models that find intent, sentiment or topics in support calls and chats.
Testing an English model
Held-back English recordings your model never trained on, to measure word and character error rate before launch.
How many hours of English speech do you need?
It depends on the model you start from and how close your users sound to the training data. These are rough starting points that come up often in speech work. Your own tests should decide.
| Goal | Rough starting point | With our English data |
|---|---|---|
| Test a model you already have | A few hours your model never trained on | A test set cut from stock and kept out of training |
| Fine-tune a multilingual model, such as Whisper or wav2vec 2.0 | Tens to a few hundred hours | Roughly 500 hours in stock covers it |
| Adapt to one domain, like banking calls | A smaller set that sounds like your users | Stock as a base, plus a custom top-up in your domain |
| Train an English model from scratch | Thousands of hours | Stock as a base, plus a larger custom collection |
Free English speech datasets or a licensed one?
Public corpora such as LibriSpeech, Mozilla Common Voice, GigaSpeech and People's Speech have done a lot for English speech research. They cover what their creators chose to record, like read sentences, crowd recordings or broadcast speech, and each comes with its own licence and terms of use. Here's how they compare with a licensed dataset.
| Topic | Public English corpora | Our English speech dataset |
|---|---|---|
| Licence | Set by each corpus, and some limit redistribution or changes | Agreed with you in writing, for what you're building |
| Consent | Covered by each project's own terms | Every speaker consented to commercial AI training |
| What it sounds like | Whatever the project recorded | Speech, prompts and conversations, with sample clips first |
| Who else trains on it | Anyone who downloads it | Set in the licence we agree with you |
| Filling gaps | Up to you | Recorded to your brief by the same network |
| Support | Community forums | A named contact from sample to delivery |
How to check an English speech sample
Half an hour with the English clips and the spec sheet answers most questions. The list works for any vendor, not only us.
| Check | What to look for | Where to find it |
|---|---|---|
| Accents | Speakers from the regions your users come from | The speaker mix on the spec sheet, and the clips |
| Everyday speech | The way your users really talk, including any mixing with other languages | Listen to the clips |
| Script | Transcripts in the script and spelling your model should output | The transcript format on the spec sheet |
| Audio | A sample rate and recording setup close to your product | The sample rate on the spec sheet |
| Numbers | Amounts, dates and phone numbers written one consistent way | Transcripts of the clips |
| Rights | Consent that covers commercial AI training, and a licence that fits | Ask for the licence terms before you buy |
From English sample clips to licensed data
Your named contact runs it from the first question to delivery.
-
01
Ask
Tell us how many English hours you need and what the model is for.
You get A reply within one business day
-
02
Sample and spec sheet
We send English sample clips and the spec sheet in reply.
You get English clips and the spec sheet
-
03
Licence and quote
We agree the licence terms and send a quote for the order.
You get Written licence terms and a quote
-
04
Delivery
The licensed English speech is delivered to you.
You get Licensed English speech with transcripts
-
05
Fill the gaps
Accents, devices or domains that are missing get recorded to your brief.
You get New English speech, recorded to your brief
Get English sample clips Start with the sample clips, then decide.
English speech data terms
The words that come up when you buy or build English speech data. The full glossary covers every data type.
- Disfluency
- A filler, repeat or restart in speech, such as um or I, I mean. Transcripts either keep them or leave them out, and the choice should be consistent.
- Accent
- The way a group of speakers pronounces a language. The same English sentence sounds different from speakers in different countries.
- Verbatim transcript
- A transcript that writes down every word as said, including fillers and restarts, instead of a cleaned-up version.
- Speaker metadata
- Details recorded about each speaker, such as gender and age, that let you check the speaker mix against your users.
- OTS dataset
- Short for off-the-shelf dataset: data already collected and ready to license before a buyer asks for it, instead of recorded to one buyer's brief.
- Word error rate (WER)
- The share of words a speech model gets wrong against a reference transcript. Lower is better.
- Character error rate (CER)
- The same idea counted in characters, often used alongside WER, since small spelling differences can make WER look worse than the model is.
- Utterance
- One stretch of speech by one speaker, such as a single prompt read aloud or one turn in a conversation.
More English and speech data
Every language in stock is on the off-the-shelf speech datasets page. Related speech datasets: Spanish, French, German and Hindi.
OTS speech datasets
Around 35,000 hours across languages, ready to license.
English data to your brief
English speech, text and translation, collected to order.
Transcription
English audio turned into timed text, checked by people.
Languages
100 languages, collected to order.
Data and model evaluation
Held-back English speech scored against your targets.
Questions about the English speech dataset
Straight answers about licensing English speech. The off-the-shelf FAQ covers questions that apply to every language.
Do you have an English speech dataset ready to license?
Yes. Roughly 500 hours of English speech, prompts and conversations are already recorded and ready to license, as part of our off-the-shelf speech pool.
What's in the English speech dataset?
A mix of scripted prompts and natural conversations in English, recorded on mobile phones, laptops and studio microphones, in quiet and noisy settings. Every recording comes with a transcript and metadata about the speaker, the device and the setting, in WAV, OGG or another common format.
Which English accents are in it?
The speaker mix is listed on the spec sheet. Ask which accents are in the hours you'd license, and the sample clips let you hear them before you commit.
Did every speaker consent to AI training?
Yes. Every speaker gave consent for their recordings to be used for commercial AI training.
How is the English dataset licensed?
Licence terms are agreed with each customer, in writing, before delivery. That includes how you can use the data and whether anyone else can license the same recordings.
How much does the English speech dataset cost?
We quote each order on its own, based on the hours you need and the licence terms. Send your request and your named contact comes back with a quote.
Can we hear English samples first?
Yes. Ask and we send English sample clips with the spec sheet, so you can check the audio before you commit.
What if we need more than 500 hours, or a specific accent?
We collect it. English speakers from our network record new speech to your brief, such as a region, an age group, a device or a domain, and it can sit alongside the hours you license from stock.
Is this the same as an English voice dataset or speech corpus?
For most uses, yes. Speech dataset, voice dataset, audio dataset and speech corpus are names for the same thing: recorded English speech with details about each recording. If you need studio-quality voice for text-to-speech, ask for the recordings made in a studio.
Can we use it as an English speech-to-text (ASR) dataset?
Yes. Every recording comes with a transcript, so it's ready for training and testing English speech-to-text models. The spec sheet shows the transcript style, so you can check it matches your pipeline before you license it.
Why not use a free English speech dataset?
Public English corpora are a good start for research. Each one has its own licence and terms of use, and they cover what their creators chose to record, such as read sentences or broadcast speech. Read the licence before you train a commercial model on one, and check that it sounds like your users.
What does OTS mean?
OTS stands for off-the-shelf: data that's already recorded and ready to license, instead of collected after you order. Our OTS English speech dataset is roughly 500 hours.
How many hours of English speech do we need?
It depends on your starting model. A test set can be a few hours, fine-tuning a multilingual model often starts at tens to a few hundred hours, and training from scratch takes thousands. Your own tests should decide.
Can we fine-tune Whisper or wav2vec 2.0 on it?
Yes. Teams commonly fine-tune open speech models like these on licensed English speech, and every recording comes with a transcript in WAV, OGG or another common format. The spec sheet shows the transcript style, so you can plan any conversion before you train.
Do you work with US teams?
Yes. We take calls in US Eastern mornings, which is evening in India. We're ISO 27001 certified, our SOC 2 report is available under NDA, and we sign GDPR data processing agreements and HIPAA business associate agreements on request.
Get English sample clips
Say roughly how many English hours you need and what the model is for. We'll send sample clips and the spec sheet.
- Your named contact replies within one business day.
- We send English sample clips and the spec sheet.
- We agree the licence terms and send a quote.
This opens your email app with the request filled in. Nothing is sent until you press send. You can also use the contact page.