Microsoft has today announced that it has entered into an agreement to buy Nuance Communications for around $19.7 billion. The deal is designed to bolster Microsoft’s cloud, AI and healthcare businesses, using Nuance’s know-how in those fields to improve the software giant’s own products. In the announcement, Microsoft specifically singles out Microsoft Cloud for Healthcare, which Nuance was already involved with, as a key beneficiary of the deal.

Microsoft CEO Satya Nadella tweeted that “AI is technology’s most important priority, and healthcare is its most urgent application.” In a statement, the CEO added that “Nuance provides the AI layer at the healthcare point of delivery, and is a pioneer in the real-world application of enterprise AI.” As well as AI, Nuance has a storied history in developing voice control, and previously provided the speech-recognition engine for Siri.

The deal is, naturally, subject to the usual regulatory checks and balances, but is expected to be done by the end of this year. Mark Benjamin, CEO of Nuance, will remain in his role while the unit is folded in to the company’s Cloud division. It’s not clear what will happen to Nuance’s customer-facing projects, but it’s likely that many of them will be folded in to Microsoft’s many-and-varied services.