We have the number four and we don’t argue with the ‘u’ because it distinguishes the number from ‘for’ and ‘fore’. But then we are faced with ‘forty’ which lacks the ‘u’. To this day I have to pause when writing numbers to ask myself, “Is this the one without the ‘u’ or is it ‘forteen’? The written number ‘forty-four’ just doesn’t look right and, frankly, dropping the ‘u’ from one of a perfectly good set of numbers is annoyingly illogical.
I don’t have time to do serious research but as far as I can work out there is no reasonable excuse for this foolishness. Somewhere about the 17th Century the ‘u’ just disappeared! So I have been experimenting. For the last year or so I have been deliberately spelling it ‘fourty’ and guess what. Nobody has corrected me.
If everybody spelled it ‘fourty’ it is almost certain that most people would not notice and the few that did (except my editor, of course) would consider it quite logical. Gradually it would appear in the dictionaries as an ‘alternate’ spelling then it would be the accepted spelling and one more irritating anomaly will have been eliminated.