Scots-Irish, Pennsylvania Dutch, Polish,[3] Ukrainian[4] and Croatian[5] immigrants to the area all provided certain loanwords to the dialect (see "Vocabulary" below).

[12] Perhaps the only feature whose distribution is restricted almost exclusively to the immediate vicinity of Pittsburgh is /aʊ/ monophthongization in which words such as house, down, found, and sauerkraut are sometimes pronounced with an "ah" sound, instead of the more standard pronunciation of "ow", rendering eye spellings such as hahs, dahn, fahnd, and sahrkraht.

[13] Older men are more likely to use the accent than women "possibly because of a stronger interest in displaying local identity...."[14] A defining feature of Western Pennsylvania English is the cot–caught merger, in which /ɑ/ (as in ah) and /ɔ/ (as in aw) merge to a rounded /ɒ/ (phonetically [ɒ~ɔ]).

This makes STRUT an unrounded counterpart of LOT, with pairs such as nut [nɑʔt] vs. not [nɒʔt] or cut [kʰɑʔt] vs. cot [kʰɒʔt] contrasting mainly by roundedness.

This is also found in contemporary Standard Southern British English, where nut [nʌʔt] also differs from not [nɔʔt] by rounding (though nought has a contrastive THOUGHT vowel instead: [no̞ːʔt], which falls together with [ɒ] in Pittsburgh).

In 1971, the Journal of the International Phonetic Association published a description of the dialect, whose author Bruce Lee Johnson notes that the auxiliary verb might is typically pronounced with nasalization, as [mɜ̃ɪ̃ʔt].

[23] That is one of the few features, if not the only one, restricted almost exclusively to western Pennsylvania in North America, but it can sometimes be found in other accents of the English-speaking world, such as Cockney and South African English.

[25] Johnson notes a tendency to diphthongize /æ/ to [ɛə] not only before nasals (as in GenAm) but also before all voiced consonants (as in bad [bɛəd]) and voiceless fricatives (as in grass [ɡɹɛəs]).

"[28] The /i/~/ɪ/ merger is found in western Pennsylvania,[6][7][15][27] as well as parts of the southern United States, including Alabama, Texas and the west (McElhinny 1999).

[6][7][15] L-vocalization is also common in the Western Pennsylvania dialect; an /l/ then sounds like a /w/ or a cross between a vowel and a "dark" /l/ at the end of a syllable.

[citation needed] Western Pennsylvania English speakers may use falling intonation at the end of questions,[6][7][30] for example, in "Are you painting your garage?"