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Dataset specification · Pilot cohort

100 speakers of Hindi Spontaneous Speech

A pilot cohort build of 100 speakers of Hindi spontaneous speech. Establishing whether a cohort definition is recruitable at all before it is scaled. Speakers talk unscripted on prompted topics — describing a process, recounting an event, arguing a position — with a moderator who prompts but does not lead.

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Structured dataset packages ready for delivery — 100 speakers of Hindi Spontaneous Speech
Volume
100 speakers
Scale
Pilot cohort
Per speaker
25–40 minutes of accepted audio per speaker
Accepted yield
60–70% of recorded time is accepted
01

How Hindi 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.

Pilot cohort — what the build is actually made ofCitiesOneStudiosA single treated roomRecruitersOne coordinatorAudio yield~50 hours at 30 minutes…Sessions per day6–8Team1 coordinator, 2 engine…
02

The specification

FieldValue
LanguageHindi (hi-IN, Devanagari)
Volume100 speakers
Equivalent50 hours at 30 minutes per speaker
Speech typeSpontaneous Speech
Per speaker25–40 minutes of accepted audio per speaker
File granularitySession-length WAV plus segmented utterance files with offsets into the parent
SegmentationPause-boundary segmentation, reviewed by a native listener rather than left to VAD
Moderator channelRecorded separately and excluded from the delivered speaker audio
Disfluency conventionFilled pauses, repetitions and false starts transcribed, not normalised away
DialectsKhari Boli, Awadhi, Braj, Bhojpuri-influenced Hindi
TranscriptionVerbatim, native-speaker, second-pass reviewed
Field recording session with a rural speaker in India — supporting 100 speakers of hindi spontaneous speech
Field recording session with a rural speaker in India
03

Designing the topic bank for Hindi

  • 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 Hindi specifically: Four-way stop contrast (voiced/voiceless x aspirated/unaspirated) that collapses in models trained on English-first acoustic units
  • Code-mixing handled explicitly rather than edited out — Urban Hindi speech is Hinglish in practice. Expect 15-40% English tokens in spontaneous speech: numbers, brands, technology terms, and whole clause switches. Any Hindi corpus that excludes English tokens will not match production traffic.
04

Running a pilot cohort Hindi build

Three to four weeks, almost entirely determined by how narrow the screening criteria are.

A single delivery with the full demographic report, since the cohort report is the point of a build this size.

Largest recruitment pool in the network. A 1,000-speaker Hindi cohort with balanced gender and 18-45 age bands is typically fielded across four cities to avoid a single-city accent bias.

ParameterAt this volume
CitiesOne — Delhi, Lucknow
StudiosA single treated room
RecruitersOne coordinator
Audio yield~50 hours at 30 minutes per speaker
Sessions per day6–8
Team1 coordinator, 2 engineers, 3 transcribers
05

Cohort design

At 100 speakers the cohort is deliberately simplified: two or three dialect groups rather than the full spread, with quotas enforced in aggregate. A build this size cannot support per-cell targets and should not claim to.

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.

DimensionTypical splitWhy it matters for Hindi
Gender50 / 50Pitch range differences change acoustic model behaviour; unbalanced cohorts bias recognition
Age18-25: 30%, 26-40: 40%, 41-60: 30%Older speakers retain conservative Hindi forms that younger urban speakers have lost
RegionUttar Pradesh / Bihar / Madhya Pradesh and othersDialect spread across 7 recognised varieties
EducationMixed, including below-graduatePrompt-reading fluency correlates with education and skews prosody
ConditionStudio / quiet room / fieldMatch the noise profile of your deployment
06

Hindi-specific considerations

  • Four-way stop contrast (voiced/voiceless x aspirated/unaspirated) that collapses in models trained on English-first acoustic units
  • Urban Hindi speech is Hinglish in practice. Expect 15-40% English tokens in spontaneous speech: numbers, brands, technology terms, and whole clause switches. Any Hindi corpus that excludes English tokens will not match production traffic.
  • Public Hindi corpora skew heavily towards read newspaper text from educated urban speakers in Delhi and NCR. Rural Bihar and eastern UP speech, elderly speakers, and low-literacy speakers reading prompts aloud are largely absent.
07

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
  • Inconsistent Devanagari vs romanised spelling for the same English loan word
  • Nukta characters (क़ ख़ ग़ ज़ फ़) applied inconsistently by transcribers

100% content QA, plus per-speaker demographic verification against the screening record.

08

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
09

Risks at pilot cohort in Hindi

Cost at this band is driven by: Screening narrowness dominates; the recording itself is a minor cost at this size.

  • Narrow criteria can make a cohort unrecruitable at any price, which is exactly what this band exists to find out
  • 100 speakers cannot support per-dialect evaluation — treat the results as directional
  • Hindi carries 7 recognised varieties across Uttar Pradesh, Bihar, Madhya Pradesh, so the quota matrix is wider than the headline volume suggests
  • Public Hindi corpora skew heavily towards read newspaper text from educated urban speakers in Delhi and NCR. Rural Bihar and eastern UP speech, elderly speakers, and low-literacy speakers reading prompts aloud are largely absent.
10

Deliverables

  • WAV audio to your naming convention, with the per-file manifest
  • Verbatim Devanagari 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
11

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 100 speakers of Hindi enough?

Enough to prove a cohort definition works and to build a small speaker-verification or accent test set. Not enough for per-dialect statistics.

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 pilot cohort Hindi build take?

Three to four weeks, almost entirely determined by how narrow the screening criteria are. A single delivery with the full demographic report, since the cohort report is the point of a build this size.

What does 100 speakers of Hindi spontaneous speech cost?

Quoted per delivered hour against this specification. At this band the drivers are screening narrowness dominates; the recording itself is a minor cost at this size. Send the spec and you get one fixed figure.

How much QA is applied at this volume?

100% content QA, plus per-speaker demographic verification against the screening record.

Quote this Hindi dataset

100 speakers, spontaneous speech, Hindi — pilot cohort. Adjust anything and send it.

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