That doesn't make much sense to me. Let's say if I were interviewed at some place using Java, Python, C and Go, why shouldn't I state my personal language preferences?
For most things as an hiring manager I'm OK with people working with their favourite language on whatever project I assign them to (as long as it isn't too esoteric; OCaml is OK, but Haskell is probably pushing it a bit too far, for instance), except when they have to work on an existing code base, in which case I wouldn't want to hire someone hating it; they'd be miserable and the resulting code would be awful.
We'll talk about this Tuesday :) People usually have a very good reason to prefer the language they're more comfortable with, because it makes them more productive. Of course, it could be easy to dispell if some guy insists on writing only assembly, or C++, vs Python. I've known a guy who wrote whole Windows GUIs in assembly, it's pure madness.
There are many valid technical reasons to rather choose C than Python, Java than Perl, or PHP than Go, Erlang rather than C++ ...
But Perl vs Python vs Ruby? Hardly any difference, extremely similar dynamic languages. It's only a matter of personal taste at this point.