Why can't I talk to bakery boy?

Just an FYI they speak Japanese, but I will write in English.

Tanjiro is the eldest in the interracial Kamado family, most of his siblings are pure Japanese, but from his mother's side, he is Korean. He lived in Northern Korea for 7 years, only until Kie finally escaped and ran to her baby father. Ever since then, all the trauma from abuse and gunshots in North Korea. Tanjiro never wanted to leave his parents side, and since they both knew Korean, they didn't bother teaching him Japanese. He finally gets the courage to go to the school his younger sister Nezuko goes to and try to make friends.

This story though, is in Zenitsu's Point of View.