> The defacto industry standard for audio ICs is I²S, an I²C-based bus optimised for audio data.

Nit: I²S has nothing to do with I²C.

(Most I²S chips also have an I²C interface since I²S only carries raw audio data, no sideband like volume control or clock configuration. But that's a separate interface and can also be SPI rather than I²C. In fact, SPI is more closely related to I²S than I²C is.)

Yeah, it's much closer to SPI.

The reason why they both follow the same naming scheme is that Philips Semiconductor (now NXP) made both.

Thanks for this comment, it lead me to look into I2S and I learned something new!