Elision in the pronunciation of "probably"

A student of mine has pointed out that in casual speech, my tendency is to pronounce the word "probably" as something like prah-lee.

I am a native speaker of American English without a specific regional dialect, as I moved frequently when young, both within the country and abroad.

I'm curious as to how widespread this pronunciation is, or if it's merely an indication that I'm a lazy speaker. Is this a regionalism I've unknowingly picked up? There is a Wiktionary entry for prolly, which indicates that I'm not alone in this pronunciation, but there's no indication of how common it is or where it's most prevalent.

Note: I'm familiar with the common tendency to skip the ba portion of the word, pronouncing it prob-lee; I'm specifically curious about the elision of both of the b sounds and the vowel between them.

Edit: I've been repeating the word over and over to myself since asking this question and realized that in particularly quick speech I seem to elide the L-sound, as well: prah-ee.

Solution 1:

The normal American English pronunciation of the canonical /'prabəbli/ is a haplologized /'prabli/, with the /b/ often lost in rapid speech to /'pra:li/. That's the "prolly" that McBain and Higgins use. Just normal speech, better recorded, but it definitely flavours the dialogue.

There is also an emphatic form, stressed on the final syllable, /pra'bli/ or /pra:'li/, which can be used as a one-word response, or as an afterthought. I remember my brother saying it a lot when he was young, so this is nothing new, though it may be more common among younger speakers. I don't know.

Solution 2:

I've come across prolly in the books of Ed McBain and George V. Higgins, set in (a thinly disguised) New York, and Massachussets, respectively.

As a South-Eastern British English speaker I sometimes (under the influence, sadly) shorten the word to probly.