How to identify speaker from voice pattern using Microsoft Speech?

Speaker recognition is a hard problem and is still an active research area. I don't think Microsoft speech api has any speaker recognition support, but not 100% sure.

I found the following article really helpful while researching the topic. It introduces the subject and also provides a very crude implementation. Probably a good place to start.

http://www.ibm.com/developerworks/opensource/library/os-sndpeek/index.html