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Dataset specification · Flagship scale

2,000 hours of Urdu Conversational Speech

A flagship scale build of 2,000 hours of Urdu conversational speech. Foundation-model input, or a multi-year corpus intended to be the reference dataset for a language. 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 — 2,000 hours of Urdu Conversational Speech
Volume
2,000 hours
Scale
Flagship 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.

Flagship scale — what the build is actually made ofCitiesTwelve or more, includi…StudiosFourteen rooms plus six…RecruitersSixteen coordinators, t…Speakers~4,000–5,000Sessions per day120–150 nationallyTeam1 programme director, 3…
02

The specification

FieldValue
LanguageUrdu (ur-IN, Perso-Arabic (Nastaliq))
Volume2,000 hours
Equivalent4,000 speakers at 30 minutes each, or 2,000 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
Audio waveforms being prepared as ASR training data — supporting 2,000 hours of urdu conversational speech
Audio waveforms being prepared as ASR 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 flagship scale Urdu build

Twenty to twenty-eight weeks, run in two or three waves. Wave one establishes the protocol and the transcription convention; later waves scale against a proven baseline rather than an assumed one.

Continuous fortnightly delivery from week four, roughly fourteen batches, each with acceptance testing and a rolling demographic reconciliation against the target quota matrix.

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
CitiesTwelve or more, including tier-2 and rural catchments — Hyderabad, Lucknow, Delhi, Bhopal, Patna
StudiosFourteen rooms plus six mobile rigs
RecruitersSixteen coordinators, three regional managers, one programme director
Speakers~4,000–5,000
Sessions per day120–150 nationally
Team1 programme director, 3 regional managers, 16 coordinators, 30 engineers, 80 transcribers, 8 QA leads
05

Cohort design

At 2,000 hours the quota matrix is enforced per cell, not in aggregate. Every dialect, age and gender combination carries its own target and is signed off individually before final acceptance, because an aggregate 50/50 split can hide a cell that was never filled at all.

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% technical QA, 5% content QA stratified across every axis, a blind 2% re-transcription audit, and a monthly cross-wave consistency review comparing early and late batches for drift.

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 flagship scale in Urdu

Cost at this band is driven by: Wave structure and the programme governance it requires; Long-tail demographic and dialect quotas, which dominate the final third of the build.

  • Drift between waves is the defining risk: audio recorded in month one and month six must be indistinguishable in convention, or the corpus splits into two datasets
  • Speaker pool exhaustion is a live constraint in all but the largest languages and shapes which cities are used
  • Staff turnover across twenty-eight weeks is a certainty, so handover documentation is part of the deliverable rather than an afterthought
  • Storage, transfer and manifest integrity become engineering problems in their own right at this size
  • 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 2,000 hours of Urdu enough?

Enough for foundation-model pre-training input in one language, or a reference corpus intended to outlive the model that prompted it.

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 flagship scale Urdu build take?

Twenty to twenty-eight weeks, run in two or three waves. Wave one establishes the protocol and the transcription convention; later waves scale against a proven baseline rather than an assumed one. Continuous fortnightly delivery from week four, roughly fourteen batches, each with acceptance testing and a rolling demographic reconciliation against the target quota matrix.

What does 2,000 hours of Urdu conversational speech cost?

Quoted per delivered hour against this specification. At this band the drivers are wave structure and the programme governance it requires and long-tail demographic and dialect quotas, which dominate the final third of the build. Send the spec and you get one fixed figure.

How much QA is applied at this volume?

100% technical QA, 5% content QA stratified across every axis, a blind 2% re-transcription audit, and a monthly cross-wave consistency review comparing early and late batches for drift.

Quote this Urdu dataset

2,000 hours, conversational speech, Urdu — flagship scale. Adjust anything and send it.

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