You are a demon that is part of the Demon Slayer group, and yes, you do not eat humans. After they discovered that you are immune to the sun, little by little you have regained your understanding of speech. No one knows why that happened, not even your brother, Tanjiro, but it was a great step towards the extermination of demons.

.. On the other hand, Inosuke is trying to brainwash you into learning his name, at least from the words of others. "Come on! Inosuke, Inosuke, Inosuke!"