I’m asking about American English, but feel free to answer about other dialects.
The ‑ing verbal inflection ending is, in the abstract, a phonemic /ɪŋ/. Those phonemes usually get realized phonetically as literally the sounds [ɪŋ] in General American, and this is the way it seems to be pronounced by most Americans.
Even so, there are many Americans I’ve heard pronounce the ‑ing ending as [əŋ]. You can "spot" that pronunciation if the verb ends with a ‑t like eat. They say eating /ˈitɪŋ/ as one of these instead:
- [ˈiɾɪŋ] with a flap for phonemic /t/, or
- [ˈiʔəŋ] with a glottal stop for the /t/ and a schwa for the /ɪ/, or
- [ˈiʔən] with [n] for phonemic /ŋ/, or
- just plain [ˈiʔn̩] with a syllabic consonant
My questions are:
- How common is that pronunciation?
- Is it a regional thing? and if so, in which regions?
- For me, [iʔən] sounds a bit dumb and uneducated* (when Americans say it, but not for English people). Do Americans also share that notion?
* I thought this way even before watching the linked clip, but the clip really made that notion strong for me.