SIR: I live in Pennsylvania Dutch country, and the use of "let" and "leave" in this area drives me crazy. Examples: "I'm going shopping and going to let my car in the lot," "Just let the window open; it isn't going to rain," "I let my golf clubs in the pro shop," "You may have my recipe, but I always let one ingredient out so you're not totally successful," "Leave me do it again." I know these examples are wrong, but when challenged I can't say why. Can you help? - Nan T.

ANSWER: Fascinating. All I know (if anything) about Pennsylvania Dutch usage appeared many years ago in a magazine cartoon showing a house in that area with a sign on the front door: "Button don't bell. Bump."Of course, your examples are all wrong in customary usage. That's because "let" means allow or permit, while "leave" means to go away from or cause to remain, and they aren't interchangeable. But if that's the way all your neighbors talk, I wouldn't try to change them. There are too many of 'em, and, besides, it's what you might call regionalism. Tell them to let you talk your way and you'll leave them talk their way.

SIR: Is it correct to use "12 a.m." and "12 p.m." - or should it be "12 noon" and "12 midnight"? - Leslie P.

ANSWER: The forms recognized by the U.S. Naval Observatory are "12 a.m." for noon and "12 p.m." for midnight.