dull / doll merger

Some people pronounce DULL and DOLL, GULF and GOLF, BULL and BALL (Bullshit/Ballshit) in the same way. All with /Q/.
Is it a regional thing or a personal choice?
I guess it's a merger in production, but not in perception.

Vlad, first of all let me congratulate you on your coming out. As for your question, yes, I believe it's probably a merger in production. I merge gulf and golf but not ball and bull.

Such is found in the dialect here, but only inconsistently (in that certain words are affected while others are not). For instance, "gulf" and "golf" are normally merged as [ˈgɒʊ̯f], while "bull" and "ball" are left unmerged as [ˈbɯː]/[ˈbʊː] and [ˈbɒːʊ̯] and "dull" and "doll" are left unmerged as [ˈdʌːɯ̯] and [ˈdɑːɯ̯]. There are other words that are affected, such as "bulb" [ˈb̥ɒːʊ̯b̥], (the prefix) "multi-" [ˈmɒʊ̯̆tae̯], "multiply" [ˈmɒʊtɨʔpx̆ɰae̯], (the prefix) "ultra-" [ˈɒʊ̯tʃɹ̠əː], and "ultimate" [ˈɒʊ̯tɨ̃ːmɨʔ], but there does not seem to be any clear rhyme and reason to it except that more learned words are less likely to be affected (except that some of the words that are affected, as shown here, are not exactly core vocabulary either).