I am good at or in English

[Kohyoongliat]

I am good at/in English.

Which is the correct preposition?

Thanks.

[Torsten]

I wouldn’t use either. How about: ‘My English is very good’ or ‘I’m really good at writing essays in English’.

[Anglophile]

As I teach, the word good takes only the fixed preposition at in such contexts.