charlie2 said:
Wonderful! That's exactly my question. That has been my question actually but I don't know how to phrase it, until I read that quotation.
One more example, if you would allow me.
Il est bon en anglais mais il l'est moins qu'en francais. Is that correct?
In all this we really need someone else to confirm what I'm saying as I am only saying what sounds ok to me (and obviously as a non-native speaker this may not be what sounds good to a native!!). Anyway with that proviso in place, and since all the French seem to be having a late lunch I'll carry on...
No your sentence doesn't sound quite right to me. You want to say "he is good at English, but less so than at French". Right?
Your French phrase is fine grammatically, but I don't think it works because you have "bon" as the adjective plus "moins" later and you wouldn't say "moins bon". If you change the adjective to "fort" from "bon" then I would say it works. It would be better to say, though "il est fort en anglais, mais il l'est encore plus en français". I think!!!
I'm getting a bit out of my depth here so let's wait for other speakers' opinions in case I am leading you down the garden path!!