NatWest has improved the accuracy of its AI speech recognition technology, helping it to better understand the range of accents and everyday language used by customers across the UK.

The project, which was undertaken in partnership with Nvidia, supports the bank's new Spending Insights tool, a conversational AI service that allows customers to explore their finances using voice or text. The feature is currently being tested with 75 per cent of Royal Bank of Scotland customers ahead of a wider rollout across NatWest Group.

NatWest said the collaboration reduced the number of words misheard by the speech recognition system by 20 per cent across the accents tested, improving its overall word error rate.

The bank combined Nvidia’s Nemotron automatic speech recognition technology with its own AI models, which interpret customer requests and generate responses.

To improve the system, NatWest asked 90 colleagues from across the UK to record around 3,000 banking-related questions using their own accents and natural speaking styles. Participants included speakers with Glaswegian, Welsh, Northern Irish, Yorkshire, Midlands and Southern English accents, as well as non-British accents.

Researchers found that speech recognition systems often struggled with merchant names, financial terminology and dates. In one example, the phrase “last quarter” spoken by a Scottish participant was transcribed as “last water”.

NatWest later expanded the work using anonymised contact centre transcripts to help the model better understand real-world banking conversations. The bank said the transcripts remained within its secure environment and that no customer data was shared with Nvidia.

The Spending Insights tool allows customers to ask questions about their spending, discuss trends and receive personalised insights through natural conversations, while interactive charts and visualisations provide additional context.

Maja Pantic, chief AI research officer at NatWest Group, said: “We are using AI to strengthen our relationships and better support customer needs. That means customers being able to interact with us in a way that feels natural to them. If they choose to speak to AI, the technology needs to understand the different accents, words and everyday language used across the UK.

"We are continually learning and improving how we use AI to make banking simpler, more personal and more responsive, while maintaining the trust customers place in us."

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