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  • 1 min read

Understand your customers better with constrained speech recognition 


In today’s voice-first world, it’s not enough for systems to simply hear what users say. They need to understand it with precision.  In high-stakes environments like healthcare, finance, or enterprise IT, voice interfaces must balance natural conversation with strict control over vocabulary and intent. Many organizations rely on voice AI agents to collect critical information. This can include account numbers, credit card numbers, tracking codes, prescription identifiers, and more! Accuracy isn’t optional in these scenarios. Even a single misrecognized digit can derail a customer experience. Traditional speech recognition systems often struggle with these inputs, leading to frustration and costly errors. 

That’s why we’re introducing Constrained Speech Recognition, a new capability in Dynamics 365 Contact Center designed to deliver highly accurate recognition for structured voice inputs. Unlike open-ended speech recognition, which tries to interpret anything a user might say, constrained systems use grammars. Grammars are structured rules that define exactly what the system should recognize, making them ideal for structured workflows and regulated domains. These rules typically use the Speech Recognition Grammar Specification (“SRGS”) format, an industry standard used by enterprises worldwide, and can include logic for validation, positional constraints, and even checksum verification.

Grammars are ideal for: 

  • Alphanumeric strings like confirmation codes, member IDs, Vehicle Identification Numbers (VIN), and package tracking numbers 
  • Constrained lists such as department names or product SKUs 

Subsequently, this approach ensures: 

  • High containment, in which only expected inputs are recognized 
  • Improved accuracy, especially in noisy environments
  • Reduced error rates compared to traditional speech recognition systems 

As voice systems continue to evolve into agentic architectures with non-deterministic conversations, constraint will play a critical role in ensuring specific outputs remain accurate, secure, and user-friendly. If your business depends on precise voice input, Constrained Speech Recognition is your next step forward. It’s not just about hearing, it’s about understanding—reliably and securely.

Learn more 

Watch a quick video introduction.

To learn more about this modality of speech recognition, read the documentation: Use external speech grammars | Microsoft Learn

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