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Dataset specification · Pilot scale

50 hours of Urdu Conversational Speech

A pilot scale build of 50 hours of Urdu conversational speech. Proving that the specification survives contact with real speakers before anyone commits a budget to it. Two speakers hold an unscripted conversation seeded with a scenario, recorded on separate channels so overlap and turn-taking survive into the delivered files.

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Two speakers recording natural conversational speech data — 50 hours of Urdu Conversational Speech
Volume
50 hours
Scale
Pilot scale
Per speaker
20–30 minutes of accepted audio per speaker, in pairs
Accepted yield
55–65% of recorded time is accepted
01

How Urdu conversational speech is captured

Two speakers hold an unscripted conversation seeded with a scenario, recorded on separate channels so overlap and turn-taking survive into the delivered files.

A 45–60 minute paired session with both speakers on isolated microphones, either in adjacent treated rooms or split-mic in one room with bleed measured and logged.

Yield at this style: 55–65% of recorded time is accepted. Overlap regions, crosstalk bleed and one-sided stretches all cost delivered time. The lowest-yield studio style we run, and priced accordingly.

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
LanguageUrdu (ur-IN, Perso-Arabic (Nastaliq))
Volume50 hours
Equivalent100 speakers at 30 minutes each, or 50 speakers at one hour each
Speech typeConversational Speech
Per speaker20–30 minutes of accepted audio per speaker, in pairs
ChannelsTwo, one per speaker, never mixed down before delivery
Channel isolationBleed measured per session and logged; sessions over threshold are re-recorded
OverlapPreserved, timestamped and labelled rather than edited out
File granularityPer-channel session WAV plus a turn-level manifest with speaker IDs
DialectsDakhini (Hyderabad), Lucknawi, Dehlvi, Bihari Urdu
TranscriptionVerbatim, native-speaker, second-pass reviewed
Annotators writing prompts and responses for LLM training data — supporting 50 hours of urdu conversational speech
Annotators writing prompts and responses for LLM training data
03

Designing the scenarios for Urdu

  • Scenario seeds rather than scripts — a disagreement to resolve, a plan to make, an experience to compare
  • Pairing designed deliberately: familiar pairs produce natural interruption, stranger pairs produce polite turn-taking, and you need both
  • Scenarios that invite disagreement, because agreeable conversation produces almost no overlap to train on
  • Register mixed across pairs so the corpus is not uniformly formal
  • Built against Urdu specifically: Shares most phonology with Hindi but adds Perso-Arabic phonemes (/q/, /x/, /ɣ/, /z/, /f/) that many speakers merge
  • Code-mixing handled explicitly rather than edited out — Spoken Urdu and spoken Hindi are largely mutually intelligible; the distinction is mainly lexical and orthographic. Decide up front whether transcription is in Nastaliq, Devanagari, or both.
04

Running a pilot scale Urdu 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.

Fix the script decision before fielding; retro-transcribing a Nastaliq dataset into Devanagari after delivery costs as much as the original transcription pass.

ParameterAt this volume
CitiesOne, usually the densest pool for the language — Hyderabad, Lucknow
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.

Effectively doubles recruitment load, since speakers are booked in matched pairs and a single drop-out cancels the whole session. Plan on 20–25% over-recruitment.

DimensionTypical splitWhy it matters for Urdu
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 Urdu forms that younger urban speakers have lost
RegionUttar Pradesh / Telangana / Bihar 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

Urdu-specific considerations

  • Shares most phonology with Hindi but adds Perso-Arabic phonemes (/q/, /x/, /ɣ/, /z/, /f/) that many speakers merge
  • Spoken Urdu and spoken Hindi are largely mutually intelligible; the distinction is mainly lexical and orthographic. Decide up front whether transcription is in Nastaliq, Devanagari, or both.
  • Indian Urdu specifically, and Dakhini in particular, are absent from public data dominated by Pakistani Urdu broadcast speech.
07

Quality gates for conversational speech

  • Channel bleed measured on every session and rejected above the agreed threshold
  • Diarisation labels verified against the isolated channels rather than inferred from the mix
  • Turn boundaries and overlap regions checked by a native listener
  • Speaking-time balance per pair audited, so a dominant speaker does not silently halve the session's value
  • Right-to-left Nastaliq tooling errors and diacritic loss
  • Merged phonemes transcribed by sound rather than by etymology, or vice versa, inconsistently

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 conversational speech sessions

  • Crosstalk bleed that makes clean per-speaker training targets impossible to recover afterwards
  • One speaker dominating, leaving a pair that delivers half the expected audio
  • Unnatural politeness between strangers, producing clean but unrepresentative turn-taking
  • Scheduling attrition — both speakers have to show up, so no-show rates compound rather than add
09

Risks at pilot scale in Urdu

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
  • Urdu carries 5 recognised varieties across Uttar Pradesh, Telangana, Bihar, so the quota matrix is wider than the headline volume suggests
  • Indian Urdu specifically, and Dakhini in particular, are absent from public data dominated by Pakistani Urdu broadcast speech.
10

Deliverables

  • WAV audio to your naming convention, with the per-file manifest
  • Verbatim Perso-Arabic (Nastaliq) transcripts with utterance-level timestamps
  • Speaker-turn segmentation with start and end timestamps
  • Overlap regions marked with participating speaker IDs
  • Backchannel and interruption markers
  • Per-pair relationship metadata: familiar or stranger
  • 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

  • Speaker diarisation
  • Meeting and multi-party ASR
  • Turn-taking and endpointing for voice agents
  • Speaker separation and target-speaker extraction

Two-party conversation does not generalise to multi-party meetings with four or more speakers, where overlap statistics change substantially. Specify that case separately.

Frequently asked

Is 50 hours of Urdu 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 conversational speech rather than another speech type?

Speaker diarisation, Meeting and multi-party ASR, Turn-taking and endpointing for voice agents are what this style is the right input for. Two-party conversation does not generalise to multi-party meetings with four or more speakers, where overlap statistics change substantially. Specify that case separately.

How long does a pilot scale Urdu 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 Urdu conversational 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 Urdu dataset

50 hours, conversational speech, Urdu — pilot scale. Adjust anything and send it.

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