Where did "sorry" get its vowel sound?

Question

Sorry has two pronunciations in my dictionary: ˈsärē and ˈsôrē. The first is the one I am interested in because, as someone pointed out to me, the or pattern in English is nearly always pronounced as "oh-r" not "ah-r". At the time, I couldn't think of any other words that pronounced or as "ah-r" but overheard someone say "tomorrow" and realized there are a few others:

• tomorrow
• sorrow
• morrow
• horror (the first o and only in some places)

The question is this: Is there a commonality between these words that allow for a är (ah-r) pronunciation? Perhaps a similar history? Does the double-r make the difference?

Answer 1

The words you list all contain what is called an "intervocalic /r/". As danorton mentioned in his answer, in Received Pronunciation an "o" preceding an intervocalic "r" is pronounced as /ɒ/ (like the "o" in "lot" or "orange"). This pronunciation also occurs in Boston, USA. In Canada, the "o" is pronounced /ɔ/ (as in "cord"). In much of the mid-Atlantic (e.g., New York, Philadelphia, and the Carolinas), the "o" is pronounced /ɑ/ (as in "card"). In the remainder of the US, the pronunciation varies between /ɔ/ and /ɑ/ depending on the word. The words you gave as examples are usually pronounced with /ɑ/, whereas words like "horrible", "origin", and "Florida" are usually pronounced with /ɔ/.

In conclusion, this phenomenon varies by dialect. It is also related to the "horse–hoarse merger," in which the vowels /ɔ/ and /o/ are merged when preceding an /r/, thus making words like horse/hoarse, for/four, war/wore, or/oar, morning/mourning, &c., homophones.

Answer 2

These two pronunciations are very typical differences in dialect and I suspect that your reference is from an American English dictionary. The first pronunciation is typical of dialects around the U.S. Great Lakes (historically influenced by Irish immigrants — including some of my ancestors) and the second is closer to Standard British (Received Pronunciation).