Voice evaluation · Indian English
Indian English AI Voice Evaluation
Human evaluation of your speech models: MOS and preference testing for TTS, WER-in-context review for ASR, and native-speaker judgement on naturalness and intelligibility. This page covers how that works specifically for Indian English, where retroflex realisation of /t/ and /d/.
- Language
- Indian English (en-IN)
- Dialects covered
- 5
- Typical programme
- 500-2,000 hours
- Cities
- Bengaluru, Delhi, Mumbai
What changes when the language is Indian English
The service specification stays constant across languages; the linguistics do not. For Indian English, three things drive the design of a voice evaluation programme.
- Retroflex realisation of /t/ and /d/
- Dialect spread: North Indian (Hindi-substrate), Maharashtrian, South Indian (Tamil/Telugu/Kannada/Malayalam substrate), Bengali-substrate
- Indian English embeds Hindi and regional discourse markers, kinship terms, and food and place vocabulary that Western English lexicons lack.
Technical specification
| Parameter | Standard |
|---|---|
| TTS | MOS (1-5), MUSHRA, and A/B preference protocols |
| ASR | Error typing: substitution, deletion, insertion, code-switch failure |
| Panel | Native speakers of the target variety, screened and calibrated |
| Sample size | Powered per the effect size you need to detect |
| Reporting | Per-item scores plus aggregate with confidence intervals |
Indian English cohort design
Balance by substrate language, not by city alone, and tag each speaker so accent-band evaluation is possible after delivery.
| Dimension | Typical split | Why it matters for Indian English |
|---|---|---|
| Gender | 50 / 50 | Pitch range differences change acoustic model behaviour; unbalanced cohorts bias recognition |
| Age | 18-25: 30%, 26-40: 40%, 41-60: 30% | Older speakers retain conservative Indian English forms that younger urban speakers have lost |
| Region | Pan-India, with distinct regional accent bands and others | Dialect spread across 5 recognised varieties |
| Education | Mixed, including below-graduate | Prompt-reading fluency correlates with education and skews prosody |
| Condition | Studio / quiet room / field | Match the noise profile of your deployment |
Process
- Protocol design and sample-size calculation
- Panel recruitment and calibration on reference items
- Blind evaluation with attention checks
- Statistical analysis
- Report with per-error-type breakdown
Indian English-specific quality rules
- Indian-specific vocabulary flagged as errors by spellcheck-driven QA
- Numbers spoken in lakhs and crores mis-normalised into millions
- Indian address and name spelling requires a domain-specific style guide
Attention checks and reference anchors are embedded so unreliable raters are detected and excluded before analysis.
Deliverables
- Raw per-rater scores
- Aggregated results with confidence intervals
- Error-type analysis
- Recommended fix priorities
Worked example
A representative Indian English voice evaluation engagement: 500 hours from 1,000 speakers, 50/50 gender, ages 18-45, spread across Bengaluru, Delhi, Mumbai, recorded to the specification above and delivered in WAV with a per-utterance manifest.
Timeline: 1-3 weeks per evaluation round.
Where this data is missing today
Commercial English ASR is trained overwhelmingly on US and UK speech. Indian English accent data with substrate-language tagging is the fastest way to close the accuracy gap for Indian deployments.
Frequently asked
How much does Indian English voice evaluation cost?
Priced per delivered hour or unit against a written spec. The cost drivers for Indian English are dialect spread, demographic narrowness and recording condition, in that order.
Which Indian English dialects are included?
By default North Indian (Hindi-substrate), Maharashtrian, South Indian (Tamil/Telugu/Kannada/Malayalam substrate), Bengali-substrate and others, tagged per speaker. You can also commission a single-dialect corpus if you are targeting one region.
Can you deliver Indian English data in our format?
Yes. Raw per-rater scores is the default, but naming, schema and directory structure follow your pipeline.
How long does a Indian English programme take?
1-3 weeks per evaluation round.
Request a Indian English voice evaluation quote
Hours, speakers, dialects, deadline. Send what you have.