Yes! I considered adding a bit about i2s, but since the article is already clocking at ~2500 words I thought I'd leave it to another time.
I2S is everywhere in audio.
Agreed, you can oversaturate the learning process and what you have is elegant, laid out well and wonderful, also covers the subject and I2S would be another subject.
Thanks for the kind words! I was up late last night writing this up, it's encouraging to see folks enjoy it.
In an article about I2C? They're not related, and I2S is far more specialized.
I2S is much closer to SPI than I2C. It really has nothing to do with I2C other than it connects chips together on a board.
I2S isn't really related to I2C beyond the similar name and the fact that both used to be commonly used in audio devices (I2C for control, I2S for audio data transport). I2S is pretty much just a specific incarnation of SPI with more bit-lines for more channels and a channel select line.