Localization
Much of this is well known, but for people who want to have localized versions of Portable Apps this may come in handy:
Oh, btw, if you want to use another language than English, you should always choose multilingual 
7-Zip Portable:
Choose your language in Tools -> Options
AbiWord Portable:
Choose your language in Extra -> Preferences
Audacity Portable:
Choose your language in Edit -> Preferences
ClamWin Portable:
I have no idea. I don't think it's available in other languages than English.
FileZilla Portable:
Choose language in Edit -> Settings -> Interface settings -> Language