While on the topic of being nit-picky (Germanic as opposed to German—what the poster obviously intended to use), the Normans brought French (a Romance language) into English.
Recent DNA Analysis has shown that the English are still mostly Celtic. Especially the female DNA. So when I think of the English, I think of them as more Celtic then German. That is what the DNA confirms. So the Normans were Celtic Gaulish French ? Not Germanic Frankish French ? I had the understanding that the Franks were the Germanic tribe that conquered and ruled over the Celtic Gauls.