「まがりなりにも通じている」ということと「正しい英語を使っている」ということには雲泥の差があります。

「」「」。

There's a world of difference between 'getting by however imperfectly' and 'using correct English.'

Literal

'Somehow-or-other understood' [quotative-ということ][and-と] 'correct English [object-を] using' [quotative-ということ][at-に][topic-は] vast difference [subject-が] exists.

まがりなりにも 'however imperfectly, in some rough fashion.' 雲泥の差 is a four-character idiom: 雲 'cloud' + 泥 'mud' + の差 'difference' — 'a difference as vast as between clouds and mud.' The sentence contrasts mere communication with linguistic correctness — a common debate in language learning.