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Dataset specification · Evaluation scale

100 hours of Urdu Conversational Speech

An evaluation scale build of 100 hours of Urdu conversational speech. Building a benchmark or evaluation set that is large enough to trust, or fine-tuning a narrow domain. 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 — 100 hours of Urdu Conversational Speech
Volume
100 hours
Scale
Evaluation 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.

Evaluation scale — what the build is actually made ofCitiesTwo, chosen for dialect…StudiosTwo rooms running in pa…RecruitersTwo coordinatorsSpeakers~200–240Sessions per day12–16 across both citiesTeam2 coordinators, 4 engin…
02

The specification

FieldValue
LanguageUrdu (ur-IN, Perso-Arabic (Nastaliq))
Volume100 hours
Equivalent200 speakers at 30 minutes each, or 100 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
Data visualisation of studio and field recording coverage across India — supporting 100 hours of urdu conversational speech
Data visualisation of studio and field recording coverage across India
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 an evaluation scale Urdu build

Four to six weeks. Two cities running in parallel means recruitment and recording overlap rather than queue behind each other.

Three batches at roughly two-week intervals, each one a self-contained, speaker-disjoint slice you can evaluate independently.

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
CitiesTwo, chosen for dialect contrast — Hyderabad, Lucknow
StudiosTwo rooms running in parallel
RecruitersTwo coordinators
Speakers~200–240
Sessions per day12–16 across both cities
Team2 coordinators, 4 engineers, 6 transcribers, 1 QA lead
05

Cohort design

At 100 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% technical QA, 25% content QA, escalating to full review on any batch that fails the agreed error threshold.

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 evaluation scale in Urdu

Cost at this band is driven by: Dialect spread is the main driver at this band — two contrasting cities cost more than two convenient ones; Turnaround compression, if you need it inside four weeks.

  • Two-city cohorts can hide a dialect gap that only appears when the model meets a third region
  • Transcription consistency between two city teams needs an explicit convention document or the batches will not match
  • 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 100 hours of Urdu enough?

A solid evaluation set, and enough to fine-tune an existing multilingual model on a narrow domain. Still short of what a general production model needs.

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 an evaluation scale Urdu build take?

Four to six weeks. Two cities running in parallel means recruitment and recording overlap rather than queue behind each other. Three batches at roughly two-week intervals, each one a self-contained, speaker-disjoint slice you can evaluate independently.

What does 100 hours of Urdu conversational speech cost?

Quoted per delivered hour against this specification. At this band the drivers are dialect spread is the main driver at this band — two contrasting cities cost more than two convenient ones and turnaround compression, if you need it inside four weeks. Send the spec and you get one fixed figure.

How much QA is applied at this volume?

100% technical QA, 25% content QA, escalating to full review on any batch that fails the agreed error threshold.

Quote this Urdu dataset

100 hours, conversational speech, Urdu — evaluation scale. Adjust anything and send it.

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