What TP language package did you download and install to your forum ?
You seem to have placed them correct, so it must be some other issues there.
1. Check so the language strings are really there.
2. Make sure they are named correctly
3. Make sure what standard you use, (uft-8 or iso)
If you have utf-8 you can see it in the language folder, all the files should have "filname.english-utf8.php"
And if they dont, you have ISO