You don't have to have an ivy-league degree or be an English major to have perfect grammar.

你没有必要获得常春藤联盟那样的学位或是必须是英语专业毕业，拥有完美的语法知识。

youdao

You can have absolutely perfect grammar and if you don't have the rhythm down, you won't have that native sound.

每一种语言都有自己的音乐性。如果你拥有完美的语法，但没有英语发音的韵律的话，你并不能拥有纯正的口音。

youdao

Adding to the stress is the complexity of the grammar, especially the far-from-perfect spelling system hellish past tense riddled with irregularities.

FORBES: English - The Language of Global Business?