Board Thread:Questions and Answers/@comment-76.225.56.101-20160303033214/@comment-33105383-20170914230319

One thing I haven't seen mentioned is the kanji used in her name ( お茶子 ) literally seperates into お茶 and 子

お茶 being "(o)cha", meaning tea and 子 being "ko", meaning child.

There's no real debate that the Japanese word for child romanizes to "ko". So that is probably why a lot of people in favour of the spelling Ochako finds the change to Ochaco to look weird. There's a lot of other character names ending in 子 that all get translated to -ko.

Of course though, if Kohei decided he wanted her name to be spelled as Ochaco despite the fact it's a weirder spelling, then we have to accept that is how it's spelled. It's like how some people are called Steven, and others Stephen.