These two terms are often used interchangeably, but they really should not be. They have distinct meanings.
Imagine you answer the telephone, listen for a few seconds and then say "Caroline, can you call me back? We have a bad connection. I can barely hear you." You recognized your friend Caroline's voice. That is Voice Recognition. You couldn't hear her well enough to understand her Speech. Speech Recognition is trying to understand the words being spoken.
Voice Recognition can be used like a fingerprint to identify a person. What matters is WHO said it.
Speech Recognition can be used to control a computer, navigate telephone menus, etc. What matters is WHAT was spoken.
So, if you want to be correct, use the term Speech Recognition anytime you are talking about controlling something by speaking -- even though you use your voice to do it!
You can use either term when you call us, we'll know what you mean.