[quote="it means no worries"]That's odd-In German you say "I cannot French" Instead of "I cannot speak French" That's silly

[/quote]
I didn't make the language, so I can't defend its grammatical choices; however from my understanding, they find it redundant to use the verb "sprechen" there as they feel it's a given when you say that you can't and follow it with the name of a language. It's not technically wrong to include it, but you'd get weird looks if you talked like that.
[quote="Tora"]Jules doesn't know German.

[/quote]
Ich kann gut Deutsch sprechen. Du, jedoch, kann nicht Englisch.