GetItemInfo, GetZoneText and localized client.

[Guildenstern]

Hello.
I'm new to addon developement, so I might be asking something silly, but how do I properly handle those functions so that my addon doesn't break on non-english versions of wow? I want it to check itemType in one situation, and player's zone in another, and to make certain decisions based on that. But results those functions return depend on the client's language. I've tried looking through GlobalStrings.lua, but couldn't find constants for item types and game zones. Is there easy way around this?