Which are correct:
[color=red]1-They said they would like to hire someone who spoke German, English, Italian and French. I said that I only didn’t speak Italian but could speak the other three languages.
[color=indigo]2-They said they would like to hire someone who spoke German, English, Italian and French. I said that I only couldn’t speak Italian but could speak the other three languages.
[color=red]3-I don’t only speak English. I speak French as well.
[color=indigo]4-I can’t speak only English. I can speak French as well.
They said they would like to hire someone who spoke German, English, Italian and French. I said that I only didn’t speak Italian but could speak the other three languages.
-Use of ‘only’ in that particular context isn’t totally wrong – you are using it for emphasis – but it sounds odd. I would avoid it in anything but informal conversation. It would be enough to speak the sentence without ‘only’.
2-They said they would like to hire someone who spoke German, English, Italian and French. I said that I only couldn’t speak Italian but could speak the other three languages.
As above, I would omit ‘only’.
‘Couldn’t’ and ‘didn’t’ are both acceptable, which is what I think you were focused on when you wrote those examples.
3-I don’t only speak English. I speak French as well.
4-I can’t speak only English. I can speak French as well.
Both ‘don’t’ and ‘can’t’ are acceptable. The placement of ‘only’ as it appears in sentence 3 is preferable in both sentences.
2-They said they would like to hire someone who spoke German, English, Italian and French. I said I couldn’t have spoken Italian but the other three, yes.
All right. I suppose, the rest you accept as correct.
In addition, is it also possible to use “though” instead of “yes”?
“I said I couldn’t speak Italian but the other three, though.”
Usage of “though” at the end of some sentences is hard for me to adapt (to become familiar with). I’d like that someone explain usage of “though” in English. At least, when to use it and why?
‘Though’ doesn’t mean ‘yes’. Its technical name is ‘contrastive adverb’ and it has the sense of ‘however’. It often comes at the end of a sentence and is mainly used in conversational language referring back to something said earlier. Take this as an example: I’ve stayed at the hotel many times. I wouldn’t recommend its food, though.