Speech data collection · বাংলা
Bengali 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 Bengali, where inherent vowel is realised as /ɔ/ or /o/, which breaks g2p rules copied from devanagari-based systems.
- Language
- Bengali (bn-IN)
- Dialects covered
- 5
- Typical programme
- 500-2,000 hours
- Cities
- Kolkata, Siliguri, Durgapur
What changes when the language is Bengali
The service specification stays constant across languages; the linguistics do not. For Bengali, three things drive the design of a speech data collection programme.
- Inherent vowel is realised as /ɔ/ or /o/, which breaks G2P rules copied from Devanagari-based systems
- Dialect spread: Kolkata standard (Rarhi), Sylheti-influenced, Rangpuri / North Bengal, Medinipuri
- Kolkata professional speech mixes English heavily; rural West Bengal much less. A single 'Bengali' dataset without register tags conflates two very different acoustic and lexical distributions.
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 |
Bengali cohort design
Tag every speaker as Indian Bengali and record district of origin; mixing in Bangladeshi speech without tags is a common and costly dataset defect.
| Dimension | Typical split | Why it matters for Bengali |
|---|---|---|
| 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 Bengali forms that younger urban speakers have lost |
| Region | West Bengal / Tripura / Assam (Barak Valley) and others | Dialect spread across 5 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
Bengali-specific quality rules
- Three sibilant characters chosen inconsistently for the same sound
- Bangladeshi vs Indian Bengali orthographic conventions mixed within one dataset
- Verb conjugation register (cholit vs sadhu) normalised by transcribers
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 Bengali speech data collection engagement: 500 hours from 1,000 speakers, 50/50 gender, ages 18-45, spread across Kolkata, Siliguri, Durgapur, 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
Indian Bengali is under-collected relative to Bangladeshi Bengali, and North Bengal and Tripura varieties are almost entirely missing.
Frequently asked
How much does Bengali speech data collection cost?
Priced per delivered hour or unit against a written spec. The cost drivers for Bengali are dialect spread, demographic narrowness and recording condition, in that order.
Which Bengali dialects are included?
By default Kolkata standard (Rarhi), Sylheti-influenced, Rangpuri / North Bengal, Medinipuri and others, tagged per speaker. You can also commission a single-dialect corpus if you are targeting one region.
Can you deliver Bengali 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 Bengali programme take?
Typical: 3-6 weeks for 100-500 hours in a single language; multi-language programmes run in parallel.
Request a Bengali speech data collection quote
Hours, speakers, dialects, deadline. Send what you have.