Speech recognition is using your voice to control the computer. Older versions of Office included speech recognition. Customers who use a newer version of Office, but who are not Office 365 subscribers, can use the Windows feature.
For speech recognition within Word, Outlook, and PowerPoint, buy an Office 365 subscription, which includes Dictation. If you're already an Office 365 subscriber, make sure you have the latest version of Office.
To set up speech recognition, go to the instructions for your version of Windows:
If your operating system is Microsoft Windows XP, you must run a previous version of a Microsoft Office system program to use speech recognition features.
Are you looking for Text-to-speech? See How to configure and use Text-to-Speech in Windows XP or Hear text read aloud with Narrator.
Excel has text-to-speech functionality built in to the program. To use text-to-speech commands in Excel, see Converting text to speech in Excel.