Letter repetition

In the above conversation you will notice two uses of repeated letters, both consonants and vowels.
I noticed this happens a lot in American English ONLINE, and I think its primary purpose is to provide an emotional inflection and convey the tone of the statement.
"Why not just use more precise words to convey your tone?" a fussy person might ask.
Because, we're just chattin' teach, and we don't care to. This way is more expedient, and works just as well.

The main tones to be inferred by letter repetition are:

Enthusiasm: Not a scientific fact or anything, but I think enthusiastic inflection via this method tends to happen on vowels. "Oooh!" "Yaaaay," for example, because that mimics natural speech, where a cry of excitement would expel more air via a longer vowel.

A lack of enthusiasm: Drawing out the last letter in a word (often a consonant) can express what in real conversation would be a promotion of the word's stress in the sentence. For example, "Let's nottt go to see 'When in Rome.'"

Sarcasm: The same can also denote sarcasm. "She looks just like a modelllll. Not." Drawing out the last letter can imply in speech it would be mocked.

The basic lesson here is that adding an extra letter (or letters) marks a word, letting the other person know that the speaker (or typer) has an unexpected relationship to the word in the context of the sentence.

Isn't that just totally dumbbbbb? No? Yaaaaay.