Sumatra is translated into many languages but we rely on you to help us keep translations for your language up to date.
To help us translate Sumatra:
To get notified about new strings that need to be translated you can subscribe to an rss feed for your language in an RSS reader of your choice (e.g. is rss feed for changes in German language)

The meaning of & in translations

& means that the following character is the hot key. For example, &File means that f key is a hot key in menu items etc. Hot keys are rendered with underline in menu items (although it can be disabled system-wide).
You don’t have to add hot keys in translations - those are for convenience and easier use with a keyboard.
In translated text a different character could be an accelerator.
See for more information.