verb
BAD : The dialogue in this video is very difficult to catch.
GOOD : The dialogue in this video is very difficult to understand.
BAD : At that time I couldn't speak or catch English at all.
GOOD : At that time I couldn't speak or understand English at all.
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Catch (= hear and/or understand) is used only in connection with what someone has just said: 'I'm afraid I didn't quite catch the last point. Could you go over it again?' 'Did either of you manage to catch her name?'