Japanese speech dataset, roughly 500 hours ready to license
Our OTS Japanese speech dataset is roughly 500 hours of Japanese speech, prompts and conversations, already recorded by Japanese speakers in our 30,000+ network, with consent from every speaker for commercial AI training. License it now and train your Japanese speech recognition model without waiting on a new collection.
- ~500 h of Japanese 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 Japanese speech dataset?
The IndecalAI OTS Japanese speech dataset is roughly 500 hours of Japanese speech, prompts and conversations, recorded by Japanese 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.
Japan is one of the largest markets for voice assistants, in-car voice and call center automation, with users who expect natural, polite speech. Japanese mixes three scripts and no spaces, so it needs transcripts made for Japanese.
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? Japanese speakers from our 30,000+ network record new speech to your brief, and our Japanese data page covers what we collect to order.
Japanese speech dataset at a glance
- Hours
- Roughly 500 hours, already recorded
- Language
- Japanese (日本語), ja
- Content
- Speech, prompts and conversations
- Consent
- Every speaker consented to commercial AI training
- Speakers
- Japanese 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
- Japanese 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 Japanese recording
What you get with each Japanese recording, and how it was made. The spec sheet adds the numbers for your order.
| Detail | In the Japanese 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 Japanese speech looks like
Roughly 500 hours sounds abstract until you play it: about 21 days of Japanese 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 Japanese 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.
Japanese at a glance, for speech teams
The facts that shape a Japanese speech project, from who speaks it to how it's written. Our Japanese data page covers what we collect to order.
Speakers
~126 million
people speak Japanese, about 124 million of them natively (Ethnologue, 2026).
Where it's spoken
Japan
Spoken almost entirely in Japan, with communities in Brazil, the US and elsewhere.
Script
漢字・かな Kanji and kana
A mix of kanji characters and two kana syllabaries, written without spaces between words.
Family
Japonic
A Japonic language with no close relatives outside Japan and the Ryukyu Islands.
Varieties
Standard and regional
Standard Japanese is based on Tokyo speech, while Kansai and other regional varieties differ in pitch accent and words.
Codes
ja · jpn
ISO 639-1 and ISO 639-3 codes. Locales speech APIs often use: ja-JP.
Japanese speech dataset, voice dataset or speech corpus?
Speech dataset, voice dataset, corpus: the names overlap. Here's how they differ, and where our Japanese data sits.
Japanese speech dataset
The general term
Recorded Japanese speech with details about each recording, for training and testing speech models. The name this page uses.
Japanese 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.
Japanese audio dataset
A wider term
It can include music or background sound. Ours is speech audio: Japanese speech, prompts and conversations.
Japanese speech corpus
The research name
A structured collection of recordings and their details. Commercial datasets are corpora too, licensed instead of published.
Japanese ASR or speech-to-text dataset
Speech plus what was said
For training a model that turns Japanese audio into text. Every recording in our Japanese dataset comes with a transcript.
Japanese voice data for assistants
Polite and casual speech
Assistants hear both polite and casual Japanese. Ask which registers are in the hours you license.
What makes Japanese hard for speech recognition
Four things that catch out Japanese speech models, and what to listen for when you check a sample from anyone, us included.
English loanwords in Japanese
Japanese uses many English loanwords, said the Japanese way and written in katakana, like アプリ for app. Transcripts have to spell them consistently, so check how a sample handles them.
Three scripts and no spaces
One Japanese sentence can mix kanji, hiragana and katakana, with no spaces between words. Decide how transcripts should write each word, then check the samples match.
Accents across Japan
Tokyo, Kansai, Tohoku and Kyushu speech differ in pitch accent, words and endings. Check that the speaker mix covers the regions your users come from.
Politeness levels
Japanese changes its verbs and words with politeness, so the same request sounds very different to a customer and to a friend. A voice product needs speech in the register its users use.
What teams build with a Japanese speech dataset
Where ready-recorded Japanese speech tends to go. These are kinds of work, not client names.
Japanese speech recognition
Train or fine-tune a Japanese speech-to-text model, or adapt a multilingual model so it handles Japanese well.
Voice bots and IVR
Teach a voice bot how Japanese callers actually ask for things, in the words and accents they use.
Customer service calls
Japanese speech for models that route, transcribe or summarize customer calls about accounts, orders and claims.
Voice in the car and at home
A Japanese base for in-car assistants and smart devices, before recording commands in the real setting.
Support and speech analytics
Japanese conversations for models that find intent, sentiment or topics in support calls and chats.
Testing a Japanese model
Held-back Japanese recordings your model never trained on, to measure word and character error rate before launch.
How many hours of Japanese 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 Japanese 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 a Japanese model from scratch | Thousands of hours | Stock as a base, plus a larger custom collection |
Free Japanese speech datasets or a licensed one?
Public corpora such as ReazonSpeech, the Corpus of Spontaneous Japanese (CSJ), Mozilla Common Voice and FLEURS have done a lot for Japanese 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 Japanese corpora | Our Japanese 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 a Japanese speech sample
Half an hour with the Japanese 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 Japanese sample clips to licensed data
Your named contact runs it from the first question to delivery.
-
01
Ask
Tell us how many Japanese hours you need and what the model is for.
You get A reply within one business day
-
02
Sample and spec sheet
We send Japanese sample clips and the spec sheet in reply.
You get Japanese 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 Japanese speech is delivered to you.
You get Licensed Japanese speech with transcripts
-
05
Fill the gaps
Accents, devices or domains that are missing get recorded to your brief.
You get New Japanese speech, recorded to your brief
Get Japanese sample clips Start with the sample clips, then decide.
Japanese speech data terms
The words that come up when you buy or build Japanese speech data. The full glossary covers every data type.
- Kana
- The two Japanese syllabaries: hiragana for native words and grammar, katakana for loanwords and emphasis.
- Pitch accent
- The rise and fall in pitch inside a word, which can tell two Japanese words apart and differs by region.
- Keigo
- Polite and honorific Japanese, used with customers and in business, with its own verb forms.
- 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 instead of WER for Japanese, which is written without spaces between words.
- Utterance
- One stretch of speech by one speaker, such as a single prompt read aloud or one turn in a conversation.
More Japanese and speech data
Every language in stock is on the off-the-shelf speech datasets page. Related speech datasets: Korean, Mandarin Chinese, Cantonese and English.
OTS speech datasets
Around 35,000 hours across languages, ready to license.
Japanese data to your brief
Japanese speech, text and translation, collected to order.
Transcription
Japanese audio turned into timed text, checked by people.
Languages
100 languages, collected to order.
Data and model evaluation
Held-back Japanese speech scored against your targets.
Questions about the Japanese speech dataset
Straight answers about licensing Japanese speech. The off-the-shelf FAQ covers questions that apply to every language.
Do you have a Japanese speech dataset ready to license?
Yes. Roughly 500 hours of Japanese speech, prompts and conversations are already recorded and ready to license, as part of our off-the-shelf speech pool.
What's in the Japanese speech dataset?
A mix of scripted prompts and natural conversations in Japanese, 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.
How are the Japanese transcripts written?
Ask for the transcript style on the spec sheet: how kanji, kana and loanwords are written, and whether readings are included. You can check it against your pipeline before you license.
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 Japanese 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 Japanese 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 Japanese samples first?
Yes. Ask and we send Japanese 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. Japanese 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 a Japanese 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 Japanese 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 a Japanese speech-to-text (ASR) dataset?
Yes. Every recording comes with a transcript, so it's ready for training and testing Japanese 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 Japanese speech dataset?
Public Japanese 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 Japanese speech dataset is roughly 500 hours.
How many hours of Japanese 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 Japanese 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 Japanese sample clips
Say roughly how many Japanese 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 Japanese 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.