Mom or Mum??

When our computer crashed a while ago - we had the shop downtown install a new program - actually we didn't have much choice in the matter!! The program is out of the UK and it is funny when the spell check tells us we are spelling things wrong. I first noticed it with Savior - spell check wants Saviour - same with color, colour and neighbor, neighbour. The thing that got me laughing most was mom - what?- I DO know how to spell mom and it is M-O-M - but spell check from England wants MUM - pretty funny I think. So if the spelling in my posts is a little bit suspect - just blame it on the new program!