My son is well behaved has been pinged
My son is well behaved is a different sentence, it is a statement about my son; while I have a well-behaved son is a statement about me. My son is well-behaved would be tha mo mhac modhail in Gaelic.
So mi-mhodail is badly behaved, presumably mi- (sorry I can't type the accent) is a construction for negative, like un- in English? Is that right and can you explain when it is used?