English already has a higher percentage of Romance vocabulary than Germanic. However, many of the "base" words the language is built on are Germanic. And the romance words are fitted into the structure as if they were Germanic. But English is a borderline case. Kenneth Branagh, in his history of English, says that if things had gone on for just a little longer, French would have taken over completely. It was close.
The turning point was the loss of Normandy in 1204ish. This severed the links between France and England, with many nobles losing their lands in France and cutting off the regular influx of new blood from marriages with French nobles etc. It was this event which gradually began the slow move back towards English. By the early 1400s, even the king could speak English
...if you import so much of basic grammar from another language, how is it still English?
I think this is what has happened with Moroccan language. I.e. so much vocabulary was imported that it changed language family.
Berber was originally the local language (and is still spoken by some), but over the centuries Arabic became the overwhelming majority language. However, IIRC in a study of what percentage of Classical Arabic words are found in various Arabic dialects as one moves further away from Arabia, Moroccan was at 60% or so.
Which implies that although most of their daily vocabulary is Arabic, there is significant substrata of the original language remaining. Which also explains why outsiders from the Gulf countries have a hard time understanding them!
