CVP obeys the VXML 2.0 standard and is language and locale agnostic.
For microapps, just set the ECC variable user.microapp.locale appropriately and store your prompts on the web server in the right location.
If you are using Say It Smart out of CVP VXML you have to set up the audio file set and define where it lives.
No "native support" - that doesn't mean anything in CVP. There are WAV files shipped with the product in English for 1.wav, 2.wav and so on, but it's nothing special.
You can support any language and any locale if you make the recordings. Simple.
SalesForce.com is integrated into UCCE through software from AMC Technologies.