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Dataset specification · Pilot scale

50 hours of Malayalam Scripted Speech

A pilot scale build of 50 hours of Malayalam scripted speech. Proving that the specification survives contact with real speakers before anyone commits a budget to it. Speakers read prompts from a phonetically balanced script shown one line at a time, with retakes on any flubbed or misread line.

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Structured dataset packages ready for delivery — 50 hours of Malayalam Scripted Speech
Volume
50 hours
Scale
Pilot scale
Per speaker
20–30 minutes of accepted audio per speaker
Accepted yield
85–90% of recorded time is accepted
01

How Malayalam scripted speech is captured

Speakers read prompts from a phonetically balanced script shown one line at a time, with retakes on any flubbed or misread line.

A 45-minute booth session yields roughly 300–400 prompts. One file per utterance, cut at the prompt boundary, so alignment is exact before any forced-alignment pass runs.

Yield at this style: 85–90% of recorded time is accepted. Prompt-level retakes catch problems inside the session, so very little is discarded afterwards. This is the highest-yield style we run.

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 typeScripted Speech
Per speaker20–30 minutes of accepted audio per speaker
File granularityOne WAV per prompt, named by prompt ID and speaker ID
Prompt coverageTriphone-balanced script with digit, date, name and domain-lexicon blocks
Leading/trailing silence200 ms padded, verified automatically on every file
AlignmentPrompt text is ground truth; deviations are flagged rather than silently corrected
DialectsThiruvananthapuram, Kochi (central), Malabar / Kozhikode, Thrissur
TranscriptionVerbatim, native-speaker, second-pass reviewed
Data visualisation of studio and field recording coverage across India — supporting 50 hours of malayalam scripted speech
Data visualisation of studio and field recording coverage across India
03

Designing the script for Malayalam

  • Script built for triphone coverage rather than word coverage, so rare phone contexts appear often enough to train on
  • Digit strings, dates, currency and person names blocked separately, because these are where deployed ASR actually fails
  • Domain lexicon injected from your product vocabulary when you supply one
  • Sentence-length distribution spread deliberately, since all-short prompts produce a model that cannot handle long utterances
  • 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.

Requires literate speakers comfortable reading aloud in the target script, which is the main constraint on cohort breadth and has to be actively counterweighted.

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 scripted speech

  • Prompt-to-audio match verified by a native reviewer; a misread line is a rejected file, not an edited transcript
  • Hyperarticulation flagged — a speaker over-enunciating because they are reading produces audio that does not match deployment
  • Clipping and truncation checked at both utterance boundaries
  • Per-speaker prompt coverage confirmed, so no speaker silently skips a block
  • 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 scripted speech sessions

  • Reading voice: flat prosody and unnatural stress that trains a model on speech nobody actually produces
  • Prompt fatigue in the back half of long sessions, where accuracy drops and pace flattens
  • Speakers who are not fluent readers, which quietly biases the cohort toward higher education bands
  • Script leakage across speakers, producing a corpus that memorises sentences instead of covering sounds
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
  • Prompt ID mapped to every utterance
  • Verbatim deviation flags where the speaker departed from the script
  • Per-utterance SNR and duration in the manifest
  • 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

  • ASR acoustic model baselines
  • TTS voice building where a single speaker is recorded at depth
  • Pronunciation lexicon and G2P validation
  • Forced-alignment and phone-boundary work

Scripted audio contains no disfluencies, no false starts and no natural turn-taking. A model trained on it alone degrades sharply on real spontaneous input, so it is a baseline layer rather than a complete training set.

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 scripted speech rather than another speech type?

ASR acoustic model baselines, TTS voice building where a single speaker is recorded at depth, Pronunciation lexicon and G2P validation are what this style is the right input for. Scripted audio contains no disfluencies, no false starts and no natural turn-taking. A model trained on it alone degrades sharply on real spontaneous input, so it is a baseline layer rather than a complete training set.

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 scripted 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, scripted speech, Malayalam — pilot scale. Adjust anything and send it.

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