'tisn't...and so on, most of them predictably contractions of common verbs. Here are the ones I found most interesting -
sha'n't, which came into use after the more commonly seen shan't,- and the three nouns on the list:
y'all're, which I heard for years when I lived in Texas,
'n' (as in rock 'n' roll or fish 'n' chips), which I'll bet is most commonly printed with just one apostrophe, but obviously should have two.
bo's'nThe new word for the day is "clitic," defined as "a morpheme that functions like a word, but appears not as an independent word but rather is always attached to a following or preceding word. In English, the possessive -'s is an example."