what is meant with languages?
-> JasonPurungrit is right
but be aware to choose a language which font you have deleted!
-> decompiling, deleting the res\value\*language* directories, recompiling the framework and maybe each app
The root question is?
Why do you want to delete the languages?
there are other and better ways to get more space
Getting bored of the languages?
just dont use them...?!
Default language is set in build.prop file. Set it correct and your fav language is used even after Wipe! No mess with additional languages at all.
So... please answer the root question as not solving your root problem, only solving symptoms may not really help you.