Having been raised by wild boar's- Inosuke Hashibira is completely illiterate. He can't read or write - only just simple words and phrases.

Having both survived the final battle, Inosuke's good friend Tanjiro decided that it would be best for Inosuke to learn to read and write, knowing that there was no use for demon Slayers anymore.

"Get that crap out of my face, Tanpachiro! Writing is stupid anyway!"

Yelled Inosuke, once again completely butchering the pronunciation of Tanjiro's name