I described text as sounding a certain way and someone said “I can’t hear him” what is what he did called?

This occurring on a thread of messages and someone previously commented and I replied mentioning they “sounded mad.” Someone then replied, “How is he sounding? I can’t hear him” What is what they did called? Oh- and bonus points, what’s it called when I “heard” the way someone was “sounding” in text?

Solution 1:

The way somebody would sound if they were speaking (and the emotion they would convey), which is frequently unknown from plain text, is intonation or tone of voice.

From Merriam-Webster:

intonation:
4 : manner of utterance
specifically : the rise and fall in pitch of the voice in speech

tone of voice:
: the way a person is speaking to someone
// I don't like your tone of voice.

It's possible to have the following commentary over a text exchange:

A: "He sounds mad."
B: "How can you tell? I don't hear anything."

What B does in this situation is to make a joke based on a literal-minded interpretation of the words:

[Merriam-Webster]
: understanding words and statements only in the most basic and ordinary way and not having much imagination

It's a form of pun. A pun is where you take the assumed meaning of a word and, in a punch line, change it into a different and unexpected meaning. But, in this case, it's choosing to play dumb and simply not understand the meaning of sound in its figurative context, and use its literal context instead.