What does this inserted clause mean? 文法だけなくて > It is saying that: evidently, the way of thinking in English and Japanese is extremely different. What does the ? (Grammar only ...?) I always get confused when appears in a sentence. It is as if i am bracing for some contradiction or negative. Is their a general phrase pattern for ~

The sentence should be:

> **** ****

XXYYor XXYYXXYYXXYYetc.) means "Not only XX but also YY".

So it literally means:

"As for Japanese and English, it seems / they say that not only their grammars but also their ways of thinking are quite different."
→ "It seems / they say that Japanese and English are quite different not only in grammar but also in way of thinking."