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Dataset specification · Pilot scale

50 hours of Malayalam Spontaneous Speech

A pilot scale build of 50 hours of Malayalam spontaneous speech. Proving that the specification survives contact with real speakers before anyone commits a budget to it. 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 — 50 hours of Malayalam Spontaneous Speech
Volume
50 hours
Scale
Pilot scale
Per speaker
25–40 minutes of accepted audio per speaker
Accepted yield
60–70% of recorded time is accepted
01

How Malayalam 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 scale — what the build is actually made ofCitiesOne, usually the denses…StudiosA single treated roomRecruitersOne coordinatorSpeakers~100–120Sessions per day6–8Team1 coordinator, 2 engine…
02

The specification

FieldValue
LanguageMalayalam (ml-IN, Malayalam)
Volume50 hours
Equivalent100 speakers at 30 minutes each, or 50 speakers at one hour each
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
DialectsThiruvananthapuram, Kochi (central), Malabar / Kozhikode, Thrissur
TranscriptionVerbatim, native-speaker, second-pass reviewed
Field recording session with a rural speaker in India — supporting 50 hours of malayalam spontaneous speech
Field recording session with a rural speaker in India
03

Designing the topic bank for Malayalam

  • 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 Malayalam specifically: One of the most consonant-dense Indian languages; long geminates and clusters raise word error rates sharply
  • Code-mixing handled explicitly rather than edited out — Manglish is standard in urban and professional speech, with heavy English noun and verb insertion.
04

Running a pilot scale Malayalam build

Three to four weeks from signed specification. Recruitment is the critical path, not recording — the studio time itself is under two weeks.

Two batches: a 10-hour first batch in week two so you can run it through your pipeline while the rest is still recording, then the balance on completion.

Budget higher transcription effort per audio hour for Malayalam than for Hindi; speech rate and morphology make it slower to annotate.

ParameterAt this volume
CitiesOne, usually the densest pool for the language — Kochi, Thiruvananthapuram
StudiosA single treated room
RecruitersOne coordinator
Speakers~100–120
Sessions per day6–8
Team1 coordinator, 2 engineers, 3 transcribers
05

Cohort design

At 50 hours 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 Malayalam
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 Malayalam forms that younger urban speakers have lost
RegionKerala / Lakshadweep / Puducherry (Mahe) and othersDialect spread across 5 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

Malayalam-specific considerations

  • One of the most consonant-dense Indian languages; long geminates and clusters raise word error rates sharply
  • Manglish is standard in urban and professional speech, with heavy English noun and verb insertion.
  • Central Kerala news-reading dominates public data. Malabar and southern varieties, and fast conversational speech generally, are missing.
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
  • Old vs new script (chillu characters, Unicode normalisation) mixed within a dataset
  • Fast speech leads to dropped-word transcription errors without a second-pass QA

100% content QA. At this volume there is no reason to sample, and a pilot exists precisely to surface specification problems.

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 scale in Malayalam

Cost at this band is driven by: Fixed setup cost is amortised over very few hours, so the per-hour rate is at its highest here; Narrow demographic requirements bite hardest at small cohort sizes.

  • The specification itself is usually the risk, not delivery — pilots exist to find the clauses that do not survive contact with real speakers
  • A single-city cohort will not represent the language nationally, and reading pilot results as national is the most common mistake at this band
  • Malayalam carries 5 recognised varieties across Kerala, Lakshadweep, Puducherry (Mahe), so the quota matrix is wider than the headline volume suggests
  • Central Kerala news-reading dominates public data. Malabar and southern varieties, and fast conversational speech generally, are missing.
10

Deliverables

  • WAV audio to your naming convention, with the per-file manifest
  • Verbatim Malayalam 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 50 hours of Malayalam enough?

Enough to validate a specification, benchmark a vendor and produce a small evaluation set. Not enough to move a production model's error rate.

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 scale Malayalam build take?

Three to four weeks from signed specification. Recruitment is the critical path, not recording — the studio time itself is under two weeks. Two batches: a 10-hour first batch in week two so you can run it through your pipeline while the rest is still recording, then the balance on completion.

What does 50 hours of Malayalam spontaneous speech cost?

Quoted per delivered hour against this specification. At this band the drivers are fixed setup cost is amortised over very few hours, so the per-hour rate is at its highest here and narrow demographic requirements bite hardest at small cohort sizes. Send the spec and you get one fixed figure.

How much QA is applied at this volume?

100% content QA. At this volume there is no reason to sample, and a pilot exists precisely to surface specification problems.

Quote this Malayalam dataset

50 hours, spontaneous speech, Malayalam — pilot scale. Adjust anything and send it.

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