Nobody asked you to apologise

„I’m sorry, my English isn’t very good.„

Then forty minutes of clear, precise English. Good sentences. Exactly the right word for the thing they do every day.

When I say so afterwards, they nod politely. They think I’m being kind.

That belief started a long time ago, probably at school, and one compliment won’t move it. So look at the timing instead. The apology came first, before you had said a word. Nobody in the room had asked for it, and nobody had heard anything yet to judge.

Quick win: Start your next English call without the apology. Say hello, then go straight to your first real sentence.