Author William Safire, in a New York Times article, suggests that the use of the final “s” in terms like pop and mom probably adds a connotation of “detached intimacy” to those familiar terms:
What has become of Mommy and Daddy, and Mom and Dad?'' asks Isabelle Bradley, an irate mother from Birdsboro, Pa. ''We are becoing a nation of 'Moms' and 'Pops.'''
I have been wondering for some time why my teen-age children have been calling me ''Pops, '' which is the name of an orchestra in Boston. My suspicion is that the addition of an ''s'' to either Mom or Pop connotes an irreverent affection, or detached intimacy, that enables a young person to address a parent in a manner familial yet cool.
''Mama'' and ''Papa,'' the endearments of earlier generations, are becoming rare; they recall immigrant days, or our parents' recollections of their parents. ''Ma'' is used occasionally, ''Pa'' rarely. Like ''Dad,'' from ''dada,'' ''papa'' is rooted in baby talk, and led to an 1838 citation for ''pop,'' meaning ''father.'' Nowadays, ''Pop,'' when capitalized and used as the name for someone who is not your father, refers to a likable geezer or the grizzled night watchman.
The declension of filial address begins with a breezy ''Howzit goin', Pops?'' to a more respectful ''About my allowance, Dad,'' to a resigned and resentful ''Yes, Father.'' Going back up the scale, it is ''Thank you, Mother, I can do it myself'' to ''Mom - can you come over and baby-sit?'' to ''Seeya, Moms!''
If you are disconcerted by the addition of ''s'' to Mom and Pop, try answering by calling your son ''Sons'' or your daughter ''Daughters.'' If they seem puzzled, tell them it's the new middleaged lingo.