Shoulda
来自Big Physics
wiktionary
Written form of a reduction of should have.
etymonline
shoulda
verbal phrase, 1902, representing casual (American) pronunciation of should have. The use of a or 'a to represent a loose pronunciation of have as an auxilliary verb is attested from mid-14c. and was all but standard English until 17c. (also preserved in coulda, woulda).
