ein ausreichendes Niveau der Deutsche-Sprachkentnisse
Sorry, I corrected that incorrectly. There is an e too many in Deutsch
e-Sprachkenntnisse.
It should be "ein ausreichendes Niveau an Deutsch-Sprachkenntnissen"
Alternatives ? : . . . a) der deutschen Sprachkenntnisse erreiche. b) der Deutsch-Sprachkenntnisse erreiche.
German doesn't use the partitive genitive here, but a prepositional expression.
Don't ask me why :< German seems to run counter-intuitively to Latin in that regard:
multitudo hominum = eine Menge
von/an Leuten
gradus scientiae = ein Niveau
an (Sprach)kenntnis
quis nostrum? = wer
von uns?
but:
quot homines = Wie viele Menschen or Wie viele der Menschen ("quot hominum" would be rather rare in Latin)
Also but:
pars hominum = ein Teil der Menschen.
I don't know if there is any concrete rule ... it seems to be a matter of collocations.
Regarding Sprachkenntnisse:
Deutsch-Sprachkenntnisse is right, but it sounds rather clunky.
deutsche Sprachkenntnisse is grammatically possible, but I don't think many people would say that.
Most people would say "Sprachkenntnisse in Deutsch", I think.