Comment by jerf

It turns out that picking up tone isn't a purely human thing and hasn't been for a while. Your Google search term is "sentiment analysis". It predates LLMs.

However, LLMs are fantastic at it. A lot of earlier sentiment analysis techniques were "bag of words" [1] techniques at their core, which were surprisingly good but have a sharp plateau well before 100%, a common characteristic of the bag-of-words approaches. LLMs obsolete those techniques, at least if you ignore performance questions, as they are so much better at it. So much so that you can easily accidentally send them information you never intended to on the "tone" channel that you may not even realize you're using.

[1]: https://en.wikipedia.org/wiki/Bag-of-words_model