Waiteen for waiting
While it's reasonably common for people to drop the g in words such as waiting, hating, and dating, I seem to be stumbling upon a number of Americans additionally drawing out the final syllable of these words. Id est, they pronounce waiting (/weɪtɪŋ/) as waiteen (/weɪtiːn/). I find it oddly pleasant and easy on the ear. While I initially suspected this form to be particular to teenagers, I've since also encountered adults employing it.
Is this affectation particular to a region or class of society in the US?
There is a duplicate question. There really hasn't been much study of this phenomenon, but other people have noticed it, and it seems like it should be a feature of Californian and southwestern U.S. accents. One thing this duplicate question doesn't answer is how this process developed. I suspect it was a two-step process.
People started using /iː/ as an allophone of /ɪ/ before /ŋ/ and /ŋk/. This phenomenon is well-documented in California—see the links in the duplicate question. Since there are no English words with the phoneme sequence /iːŋ/, it doesn't create any ambiguity in language. These people would say waiteeng and waitin', because after dropping the 'g', the phoneme would still be /ɪ/, and since there's now an /n/ after it, the pronunciation would revert to /ɪn/. Having lived in California (several decades ago), I don't think I even notice this pronunciation as being unusual.
People internalized /iː/ as the actual phoneme in words like pink, king, and waiting. (This phenomenon has also been well-documented—again, see the links in the duplicate question.) Now, presumably, when these people drop the 'g', some of them keep the /iː/ phoneme, yielding the pronunciation waiteen'. This pronunciation sounds quite strange to me.
I too have noticed this phenomenon on all news channels. As an American living abroad with an ear for accents, I have become especially aware of changes to the language that have occurred since I left the country. My nieces and nephews who grew up in Ohio all use this pronunciation of -ing as -een.
Watching the news, I have noticed that some people only stretch the 'i' and drop the 'g' in the present continuous form but seem to keep it unaltered when it occurs before a noun as an adjective as in 'demonstrating protesters'. But they do say 'the protesters are demonstrateen'. It seems to be mostly northern white speakers who do this, perhaps because of an unconsciously perceived stigma of saying 'demonstratin' that for them, maybe associated with the Deep South or Afro-American English.
Having said that, I have also noticed that the verb 'to be' seems to be disappearing from the continuous verb forms as well, as in "President Trump tweeting this morning.." This could be a form of headlinese solely restricted to the news, but I can imagine that in 30 years from now we will all be saying‚ "They haveen a beer." instead of "He's having a beer." Oh yes, we will no longer differentiate between 'he' and 'she' either. Language changes!