How do I detect what Template is on & Where do I can change the forums topics

Hi, I'm trying to make a two-languajes forum. First, I install two templates, one in english, other one in spanish, but my problem is in Topics of forums, I don't know the exact name of this but for this forum is ej: Code Hacks, What I would like to do is to look for the variable that contains the "Code Hacks" array (with an if, I had no problems in do that with all my forums) and then change it to what i want. But what I want is about the template, I'm newby in PHP, so help me with this please, how can i detect what template is the user surfing my forums using. The two templates names are "English" and "Español", I think this could be maked trought a if ($template_variable? == "Español") { $topic = "Code Hacks"; }, but I don't know the variables names and in wich file are located ( I try to find these but it's a really hard to read code ).

Thanks

Really sorry for my english.