From Longman Dictionary of Contemporary Englishtalk down to somebody phrasal verbTALK TO somebodyto talk to someone as if they are stupid, although they are not SYN patronize The students felt that they were talked down to as though they were children. → talk→ See Verb table
Examples from the Corpus
talk down to • Far from being treated as adults, however, students on the course were talked down to as though they were children.• The material was written to inform, but not talk down to, consumers.• A lot of the arts fellows think Humphrey's a bit of a twit and tend to talk down to him.• He was usually available for comment and did not talk down to journalists.• I got the feeling he was talking down to me, even though I personally wired my own home exactly like that.• People interpreted it as lack of support; in addition, he talked down to people in a parental sort of way.• He just can't deal with parents and adults because he's so used to talking down to students all day.• The emphasis has switched to trying to reach the general public, rather than talk down to them. 