Microsoft Corp. is buying speech-recognition pioneer Nuance Communications Inc. (Nasdaq: NUAN) in an all-cash deal valued at $19.6 billion, gaining artificial-intelligence technology aimed at helping doctors predict patients’ needs and upgrading hospitals’ digital record-keeping. The software giant is offering to purchase Nuance at $56 a share, a 23% premium to Friday’s close. Nuance’s shares closed at $52,85 higher by 15,9%.