AI & Tech

ASR (Automatic Speech Recognition)

Automatic Speech Recognition (ASR) is the technology that converts spoken audio into text — the foundation layer beneath every transcription, speech analytics, and AI call auditing system in a modern contact center.

What Is ASR?

ASR (Automatic Speech Recognition) is the AI technology that turns spoken language into written text. When an agent and customer talk on a call, ASR is what produces the transcript — without ASR, none of the downstream technologies (transcription, speech analytics, sentiment analysis, automated call scoring, AQM) can work.

In Indian contact centers, ASR is the make-or-break layer. An ASR system that handles English well but stumbles on Hindi, Tamil, or Hinglish code-switching cannot accurately audit Indian conversations — and any QA score built on bad transcripts is unreliable.

How ASR Works

A modern ASR pipeline involves:

  1. Audio capture — Sound is recorded from the call (telephony stream, recording file, or live microphone)
  2. Acoustic modeling — A neural network maps audio features to phonemes (the smallest units of sound)
  3. Language modeling — A separate model maps phoneme sequences to likely word sequences in the target language
  4. Decoding — The system outputs the most probable transcript given the acoustic + language signals
  5. Post-processing — Punctuation, capitalization, speaker separation (diarization), and noise filtering are applied

Top systems (OpenAI Whisper, Google Speech-to-Text, Azure Speech, AWS Transcribe, Deepgram, and AI4Bharat for Indic) use end-to-end neural architectures that handle these steps jointly.

ASR Full Form Explained

ASR stands for Automatic Speech Recognition. The technology is sometimes called Speech-to-Text (STT), Voice Recognition, or simply Transcription. Strictly speaking:

  • ASR = the underlying technology (general)
  • STT (Speech-to-Text) = the same thing, more often used as the product/API name
  • Transcription = the output (a written transcript)
  • Voice recognition = a related but distinct concept of identifying who is speaking (closer to speaker ID)

ASR Accuracy Benchmarks (2026)

Accuracy is typically measured by Word Error Rate (WER) — lower is better.

| Language / Variant | Best ASR WER | Typical ASR WER | |---|---|---| | US English | 4-6% | 8-12% | | Indian English | 8-12% | 15-20% | | Hindi (clean audio) | 10-14% | 18-25% | | Hinglish code-switching | 15-22% | 25-35% | | Tamil, Telugu, Bengali, Marathi | 12-18% | 20-30% | | Telephony audio (8kHz) | adds 3-5pp WER | adds 5-10pp WER | | Heavy background noise | adds 5-10pp WER | adds 10-15pp WER |

A 20% WER means roughly 1 in every 5 words is mis-transcribed — usually fine for theme detection but problematic for compliance keyword spotting where missing a single word can change the meaning entirely.

Why ASR Matters for BPOs

Three reasons ASR sits at the foundation of every modern contact center QA program:

  1. It's the gating dependency: If ASR is wrong, everything downstream (sentiment, intent, QA scoring, compliance detection) is wrong. Indian BPOs have historically been ill-served by global ASR vendors who optimize for US English.
  2. Multilingual support is non-negotiable: A 200-agent Indian BPO running Hindi + Tamil + English campaigns needs ASR that handles all three — and the code-switching between them within the same sentence.
  3. Telephony audio is hard: Call center audio is typically 8kHz narrowband (vs 16-44kHz on consumer apps). Most consumer-tuned ASR systems lose 5-10pp WER on telephony audio without specific tuning.

ASR for Indian Languages

The Indian ASR landscape has shifted dramatically since 2024:

  • AI4Bharat (IIT Madras) released open-source models for 22 Indian languages with state-of-the-art accuracy on Indic
  • Sarvam AI built sovereign Indic ASR with strong code-switching support
  • OpenAI Whisper added native Hindi support; community fine-tunes handle Hinglish reasonably
  • Bolna, Gnani.ai, and Krira offer voice-AI products built on Indian-tuned ASR

Top vendors now publish Indic WER benchmarks rather than just English numbers — a sign the market has matured.

How Gistly Uses ASR

Gistly's audit pipeline starts with ASR. The platform uses a layered approach:

  • English calls: best-in-class commercial ASR with telephony-tuned acoustic models
  • Hindi, Tamil, Telugu, Bengali, Marathi: Indic-specialized models fine-tuned on contact center audio
  • Hinglish code-switching: a separate code-switching-aware decoder that handles Hindi-English mid-sentence

The combined system reaches 90%+ accuracy on Indian English contact center audio and 80-85% on Hinglish — high enough that QA scores built on the transcripts agree with human evaluators on 85-92% of scoring decisions.

This is the technical foundation that lets Gistly deliver 100% audit coverage in 10+ languages including Indic code-switching — and why a "global" ASR system tuned for US English isn't enough for Indian BPOs.

Frequently Asked Questions

What is the full form of ASR?

ASR stands for Automatic Speech Recognition. It's the AI technology that converts spoken audio into written text — the foundation layer beneath transcription, speech analytics, and AI call auditing.

Is ASR the same as transcription?

ASR is the technology; transcription is the output. ASR produces transcripts. Some products are sold as "transcription services" but use ASR under the hood; others are sold as "ASR APIs" and let customers build their own transcription products.

What ASR accuracy is needed for AI call auditing?

For broad theme detection, 75-80% WER accuracy is usable. For compliance keyword spotting (where missing a single word can cause false negatives), 90%+ accuracy is needed. Top platforms for Indian BPOs reach 90%+ on English and 80-85% on Hinglish in real telephony conditions.

Why does ASR struggle with Indian languages?

Three reasons: (1) training data — most global ASR systems are trained on US English audio, not Indian voice samples; (2) code-switching — Indian speakers fluidly mix English with Hindi/Tamil/etc., which most ASR models can't handle natively; (3) telephony audio quality — 8kHz Indian telephony audio adds another 5-10pp WER on top of the base error rate.

Last updated: May 2026

Browse the full glossary

Every term we use across QA, compliance, and contact center operations — defined in one place.

View all glossary terms →