сколько ему ни толкуй, он ничего не понимает— you can go on explaining till you're blue in the face, you won't make him understand; it's a waste of time trying to explain things to him
3. (с тв. о пр.; разговаривать) talk (with about); (обсуждать) discuss (with d.)
что тут много толковать— it's no use talking about it, или discussing it
♢ он всё своё толкует — he keeps on harping on the same string