All languages change over time, although some are more conservative than others. The causes of sound change have been at the center of the historical study of language for many generations. One such cause––no doubt a marginal one––is affectation, i. e., a largely unconscious imitation of a prestige pronunciation whereby a speaker of a socially lower class aspires to be considered for accession to a socially higher class by adopting a speech trait that is characteristic of the latter group.
This is apparently the cause of the recent raising of the vowel [æ], as in past, pad, and palindrome, to the vowel [a:] of arm, father, etc. among young female speakers (adolescents and younger women). As has been remarked in earlier posts, the latter (so-called broad vowel) is to be heard as the affected variant in foreign borrowings like Iran and Iraq instead of the traditional (so-called flat) vowel [æ] and native words like rather. This particular affectation is especially favored by those who wish to sound “educated” or “cultivated” despite the fact that their brand of American English in other respects merits neither of these designations.
Since this trait is an incipient one manifested by young females, it is worth noting that affectations as innovations that fall short of full-fledged changes in language typically begin among speakers who are socially less powerful but aspire through borrowed prestige to elevate themselves linguistically. If this innovation spreads beyond its original locus, it bids fair to displace the traditional norm.