Excerpt from this article:
The Internet… has recently given rise to many more takes on “yes.” There’s “yeeeeees” and “yessssss” and their many variations, which take advantage of word lengthening to lend a sense of added enthusiasm to the traditionally neutral affirmation. There’s “yiss,” which was apparently originally uttered by the “mountie duck” in a Kate Beaton webcomic and which Urban Dictionary defines as “an excitable way of saying ‘yes.’” There’s “kewl,” a sensational spelling of “cool” (or, again according to Urban Dictionary, “a kewter, more klever, kewler way of saying ‘cool'”). There’s “okie,” another playful misspelling, and “k” (“OK,” but more hurried or, depending on contextual cues, more passive-aggressive). There’s “kk,” arising from the gaming community as an abbreviated fusion of “k” and “kewl.” There’s “yas,” apparently of Glaswegian origins, another term with roots in gaming—and another one whose intentionally erroneous vowel functions as, effectively, an embedded exclamation point.
And there are also, of course, all the emoji that indicate enthusiasm and assent: the thumbs-up, the clapping hands, the prayer hands, the smiling face, the sunglasses-wearing smiley face, etc.
So “yes” has, basically, procreated: It has taken its own basic DNA and mixed it with other threads of culture, creating new words and terms and memes and pictograms that do the work of affirmation while also conveying secondary nuances: enthusiasm, hesitation, irony, delight.
…A question answered with a thumbs-up emoji or a “kk” or even a “y”? Those are ways of assenting without necessarily affirming. “I think this notion of going from ‘yes’ to less committal terms,” Baron says, “is one way of saying, ‘yeah, it’s okay, I’m not committed.’”
The flip side of that, though, is the affirmation that expresses overt enthusiasm and excitement and even joy. The distribution and dissolution of “yes” might have reached its apotheosis in “yaaas” (which is also written as “yaaaaas” and “yassssss” and “YAAAAAASSSSSS” and pretty much any other variation of those three ordered letters that you choose to type). “Yaaaas,” which functions as an affirmation and an exclamation and, occasionally, an adjective—“a sensible single syllable,” Refinery29 describes it, “that carries enough punch to make a statement, but enough sass to show you don’t really give-uh-what”…