The site seems to originate in Germany, and the language is German. Really not too hard to hit the high spots about cartridges in the German language. You only need a few basic words. Much is similar to English once you have a very short cartridge vocabulary. I can't read one sentence of social German, but I usually walk away with some understood facts reading about cartridges in that language.
I found it is also good to invest in some foreign language-English dictionaries, although they usually don't have a terrific amount ot ammunition and firearms terms in them.
One of these days we will have on this website a nice glossary of foreign language ammunition terms, and that will help us all. It is a project in progress right now.
Edited for spelling only