Dataset specification · Production scale
500 hours of Assamese Spontaneous Speech
A production scale build of 500 hours of Assamese spontaneous speech. The point at which a corpus is large enough to train a deployable model rather than adapt someone else's. Speakers talk unscripted on prompted topics — describing a process, recounting an event, arguing a position — with a moderator who prompts but does not lead.

- Volume
- 500 hours
- Scale
- Production scale
- Per speaker
- 25–40 minutes of accepted audio per speaker
- Accepted yield
- 60–70% of recorded time is accepted
How Assamese spontaneous speech is captured
Speakers talk unscripted on prompted topics — describing a process, recounting an event, arguing a position — with a moderator who prompts but does not lead.
A 60-minute session covering six to eight topics, recorded continuously and segmented afterwards into utterances at natural pause boundaries.
Yield at this style: 60–70% of recorded time is accepted. Long silences, moderator speech and abandoned topics are cut in post, so recorded hours run well ahead of delivered hours. Budget for the gap.
The specification
| Field | Value |
|---|---|
| Language | Assamese (as-IN, Assamese (Eastern Nagari)) |
| Volume | 500 hours |
| Equivalent | 1,000 speakers at 30 minutes each, or 500 speakers at one hour each |
| Speech type | Spontaneous Speech |
| Per speaker | 25–40 minutes of accepted audio per speaker |
| File granularity | Session-length WAV plus segmented utterance files with offsets into the parent |
| Segmentation | Pause-boundary segmentation, reviewed by a native listener rather than left to VAD |
| Moderator channel | Recorded separately and excluded from the delivered speaker audio |
| Disfluency convention | Filled pauses, repetitions and false starts transcribed, not normalised away |
| Dialects | Kamrupi, Goalparia, Upper Assam (Sibsagar standard), Barak Valley contact varieties |
| Transcription | Verbatim, native-speaker, second-pass reviewed |

Designing the topic bank for Assamese
- Topic banks graded by familiarity, so speakers across education and occupation bands all have something to say
- Open prompts only — anything answerable with yes or no produces thirty seconds of audio and a stalled session
- Culturally grounded topics per region, since a prompt that works in Mumbai can draw blank looks in Guwahati
- Topic rotation across the cohort so the corpus does not over-represent a handful of subjects
- Built against Assamese specifically: Assamese has the voiceless velar fricative /x/, unique among major Indian languages and routinely mis-modelled
- Code-mixing handled explicitly rather than edited out — Assamese speech mixes Hindi, English and Bengali, with substantial contact influence in Barak Valley and tea-garden communities.
Running a production scale Assamese build
Eight to twelve weeks. Cities are staggered rather than started together, so the protocol corrections found in the first city are applied before the last one begins recording.
Six to eight batches, fortnightly, each speaker-disjoint so you can train on early batches without contaminating a later evaluation split.
Expect longer fielding times and higher per-hour cost than for Hindi or Marathi; the speaker pool with transcription-grade literacy is smaller.
| Parameter | At this volume |
|---|---|
| Cities | Five to six — Guwahati, Jorhat, Dibrugarh, Silchar, Tezpur |
| Studios | Six rooms plus two mobile rigs for rural capture |
| Recruiters | Six coordinators under one programme lead |
| Speakers | ~1,000–1,200 |
| Sessions per day | 40–50 nationally |
| Team | 1 programme lead, 6 coordinators, 12 engineers, 25 transcribers, 3 QA leads |
Cohort design
At 500 hours quotas are enforced per dialect and reconciled fortnightly. Aggregate demographics are reported per batch so drift is visible while there is still time to correct it.
Screening is for willingness to talk, not literacy, which opens the cohort to speakers a scripted protocol would exclude. Expect to over-recruit by 15% for speakers who freeze on the day.
| Dimension | Typical split | Why it matters for Assamese |
|---|---|---|
| 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 Assamese forms that younger urban speakers have lost |
| Region | Assam / Arunachal Pradesh / parts of Nagaland and Meghalaya and others | Dialect spread across 4 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 |
Assamese-specific considerations
- Assamese has the voiceless velar fricative /x/, unique among major Indian languages and routinely mis-modelled
- Assamese speech mixes Hindi, English and Bengali, with substantial contact influence in Barak Valley and tea-garden communities.
- Extremely low-resource. Almost no spontaneous Assamese speech data exists publicly, and non-standard dialects have none.
Quality gates for spontaneous speech
- Segment boundary review — bad boundaries produce truncated words that poison training more than they help
- Disfluency transcription consistency audited across transcribers, since conventions drift fast on this style
- Moderator speech confirmed absent from delivered segments
- Topic distribution checked per speaker so one dominant subject does not skew the language model
- Bengali characters substituted for Assamese ৰ / ৱ
- Goalparia and Kamrupi forms standardised to Sibsagar Assamese
100% technical QA, 10% content QA stratified by city, dialect, transcriber and recording condition, with automatic escalation to 100% on any failing batch.
What goes wrong on spontaneous speech sessions
- Speakers who dry up after a minute, leaving sessions that look complete by duration but are mostly silence
- Drift into a reading register when a speaker becomes self-conscious about the microphone
- Moderator over-prompting, which turns a monologue corpus into an interview corpus
- Transcriber normalisation — quietly cleaning up disfluencies destroys the exact signal this style exists to capture
Risks at production scale in Assamese
Cost at this band is driven by: Field and rural capture ratio — mobile rig hours cost more than studio hours; Rare dialect quotas, where the last 10% of the cohort can cost as much as the first 40%.
- Speaker duplication across cities becomes a real risk at this cohort size and needs active de-duplication against voice and ID
- Rural capture depends on weather and travel in a way studio work does not, so mobile-rig batches carry schedule variance
- Quota drift compounds across six cities unless demographics are reconciled weekly rather than at the end
- Assamese carries 4 recognised varieties across Assam, Arunachal Pradesh, parts of Nagaland and Meghalaya, so the quota matrix is wider than the headline volume suggests
- Extremely low-resource. Almost no spontaneous Assamese speech data exists publicly, and non-standard dialects have none.
Deliverables
- WAV audio to your naming convention, with the per-file manifest
- Verbatim Assamese (Eastern Nagari) transcripts with utterance-level timestamps
- Filled-pause and false-start markers
- Segment offsets into the parent session file
- Topic label per segment
- Speech-rate and pause-density statistics per speaker
- Per-speaker metadata: age band, gender, region, dialect, education band
- Consent records mapped to speaker IDs
- QA report with pass rates, rejection reasons and agreement statistics
- Speaker-disjoint train / dev / test splits on request
What this trains, and what it does not
- Robust ASR for real user speech
- Language modelling on natural syntax
- Disfluency detection and removal
- Prosody and speech-rate modelling
Phonetic balance cannot be guaranteed — speakers say what they say. If you need specific phone contexts or a controlled lexicon, this style has to be paired with a scripted layer.
Frequently asked
Is 500 hours of Assamese enough?
Enough to train a deployable model for a single language, or to substantially improve a multilingual one. This is the most common production band.
Why spontaneous speech rather than another speech type?
Robust ASR for real user speech, Language modelling on natural syntax, Disfluency detection and removal are what this style is the right input for. Phonetic balance cannot be guaranteed — speakers say what they say. If you need specific phone contexts or a controlled lexicon, this style has to be paired with a scripted layer.
How long does a production scale Assamese build take?
Eight to twelve weeks. Cities are staggered rather than started together, so the protocol corrections found in the first city are applied before the last one begins recording. Six to eight batches, fortnightly, each speaker-disjoint so you can train on early batches without contaminating a later evaluation split.
What does 500 hours of Assamese spontaneous speech cost?
Quoted per delivered hour against this specification. At this band the drivers are field and rural capture ratio — mobile rig hours cost more than studio hours and rare dialect quotas, where the last 10% of the cohort can cost as much as the first 40%. Send the spec and you get one fixed figure.
How much QA is applied at this volume?
100% technical QA, 10% content QA stratified by city, dialect, transcriber and recording condition, with automatic escalation to 100% on any failing batch.
Quote this Assamese dataset
500 hours, spontaneous speech, Assamese — production scale. Adjust anything and send it.