Speech data collection · தமிழ்
Tamil Speech Data Collection
Recruited-speaker speech corpora recorded to a written specification: scripted prompts, spontaneous monologue, or both, with full speaker metadata. This page covers how that works specifically for Tamil, where extreme diglossia: written tamil and spoken tamil differ so much that read-speech corpora are near-useless for conversational asr.
- Language
- Tamil (ta-IN)
- Dialects covered
- 6
- Typical programme
- 500-2,000 hours
- Cities
- Chennai, Coimbatore, Madurai
What changes when the language is Tamil
The service specification stays constant across languages; the linguistics do not. For Tamil, three things drive the design of a speech data collection programme.
- Extreme diglossia: written Tamil and spoken Tamil differ so much that read-speech corpora are near-useless for conversational ASR
- Dialect spread: Chennai (Madras Bashai), Kongu (Coimbatore), Madurai, Nellai (Tirunelveli)
- Tanglish is the default urban register. Technology, finance, and workplace vocabulary is largely English embedded in Tamil syntax.
Technical specification
| Parameter | Standard |
|---|---|
| Sample rate | 48 kHz capture, delivered at 48/16 kHz as required |
| Bit depth | 24-bit capture, 16-bit PCM delivery |
| Format | WAV (PCM), one file per utterance or per session |
| Channels | Mono per speaker; multi-channel on request |
| Noise floor | Studio sessions below -50 dBFS; field sessions specified per project |
| Clipping | Zero tolerance; clipped takes are re-recorded, not repaired |
Tamil cohort design
Recruit by district rather than by city alone; Chennai-only cohorts produce models that degrade sharply in the south and west of the state.
| Dimension | Typical split | Why it matters for Tamil |
|---|---|---|
| Gender | 50 / 50 | Pitch range differences change acoustic model behaviour; unbalanced cohorts bias recognition |
| Age | 18-25: 30%, 26-40: 40%, 41-60: 30% | Older speakers retain conservative Tamil forms that younger urban speakers have lost |
| Region | Tamil Nadu / Puducherry / parts of Karnataka and Kerala and others | Dialect spread across 6 recognised varieties |
| Education | Mixed, including below-graduate | Prompt-reading fluency correlates with education and skews prosody |
| Condition | Studio / quiet room / field | Match the noise profile of your deployment |
Process
- Requirement lock: languages, hours, speaker count, demographic quotas, recording conditions
- Prompt design and linguistic review by native reviewers
- Speaker recruitment and screening against quota, with consent capture
- Recording sessions with real-time level and prompt-coverage monitoring
- Automated technical QA on every file (SNR, clipping, duration, silence)
- Native-speaker content QA on a defined sample, escalating to 100% on failure
- Packaging, manifest generation and delivery
Tamil-specific quality rules
- Transcribers normalising spoken Tamil into literary Tamil, destroying the acoustic-text alignment
- ழ / ள / ல confusion
- Inconsistent handling of English insertions: Tamil script transliteration vs Latin script must be fixed in the guide
Every file passes automated technical checks. Content QA is sampled at 10% by default and raised per batch when the failure rate crosses the agreed threshold.
Deliverables
- Audio files in the agreed format and naming convention
- Per-utterance manifest (speaker ID, prompt ID, duration, condition)
- Speaker metadata: age band, gender, region, dialect, education band
- Consent records mapped to speaker IDs
- QA report with pass rates and rejection reasons
Worked example
A representative Tamil speech data collection engagement: 500 hours from 1,000 speakers, 50/50 gender, ages 18-45, spread across Chennai, Coimbatore, Madurai, recorded to the specification above and delivered in WAV with a per-utterance manifest.
Timeline: Typical: 3-6 weeks for 100-500 hours in a single language; multi-language programmes run in parallel.
Where this data is missing today
Almost all public Tamil audio is literary read speech from news or scripture. Genuine colloquial Tamil, especially southern and Kongu varieties, is the single biggest gap for anyone building Tamil voice products.
Frequently asked
How much does Tamil speech data collection cost?
Priced per delivered hour or unit against a written spec. The cost drivers for Tamil are dialect spread, demographic narrowness and recording condition, in that order.
Which Tamil dialects are included?
By default Chennai (Madras Bashai), Kongu (Coimbatore), Madurai, Nellai (Tirunelveli) and others, tagged per speaker. You can also commission a single-dialect corpus if you are targeting one region.
Can you deliver Tamil data in our format?
Yes. Audio files in the agreed format and naming convention is the default, but naming, schema and directory structure follow your pipeline.
How long does a Tamil programme take?
Typical: 3-6 weeks for 100-500 hours in a single language; multi-language programmes run in parallel.
Request a Tamil speech data collection quote
Hours, speakers, dialects, deadline. Send what you have.