my 3 year old started nursery last year. he usually says "aye" instead of "yes" because that's what his family say most of the time. we don't feel this is slang or cheeky, just typically "scottish"! (and they do also use it in parliament when voting). recently he started saying "yes" a lot, and told us his new nursery teacher has told him to say "yes" in nursery, not "aye". AIBU in feeling she has no right to do this? i would be really interested to hear from people who work in this profession.