回複：

The Boston accent has a highly distinctive system of low vowels, even in speakers who do not drop [r] as described above. Eastern New England is the only region in North America where the distinction between the vowels in words like father and spa on the one hand and words like bother and hot on the other hand is securely maintained: the former contain [aː] ([faːðə], [spaː]), and the latter [ɒː] ([bɒːðə], [hɒːt]). This means that even though heart has no [r], it remains distinct from hot because its vowel quality is different: [haːt]. By contrast, the accent of New York uses the same or almost the same vowel in both of these classes: [ɑː]. The Received Pronunciation of England, like Boston English, distinguishes the classes, using [ɑː] in father and [ɒ] in bother.