I am currently adding localization support to Amber. It will be out once at least one translation is ready.
If you want to help with that particular client feel free to translate those
https://dl.dropboxusercontent.com/u/37131061/l10n.zipNote that files have UNIX style line endings so should use an editor which can handle those like Notepad++.
Save using the original UTF-8 encoding.
EDIT: also there is some additional code in the strings which allows embedding resources, text styling, or new line separators. Things like this:
$img[gfx/hud/chr/unarmed]
$col[255,128,128]{Oppressive}
i{"Ettinaz saw the signs"}
\\n
You'll will want to be careful with those and leave them as is, that is, just replace the english text but leave everything else intact.