When is otou and okaa used instead of otousan and okaasan?

Question

I was watching a Japanese series recently and a young man 25~30 years old refers to his parents as otou and okaa.

This took me by surprise as I've never even considered that that could be done. But it makes sense, it's just dropping the san which is a kind of a title/honorific.

Anyway one would assume that say otou is very very informal to the point of being rude and disrespectful or at least just young people trying to sound cool in front of their friends. But the young man in the series was actual quite a polite and cultured young man and it seemed strange to me that he would use it.

How often are otou and okaa used in what contexts etc ?

Arigatou gozaimasu

Answer 1

• You may have misheard おとん/おかん, which are common informal ways of saying father/mother in Kansai dialect, as Chocolate mentions. This should be avoided in formal settings, but in informal settings, it is safe to use them to refer to the listener's parents, too.
• If you really heard おとう and おかあ, these are fairly old-fashioned and dialectal ways of saying Father/Mother. You would usually hear them only in a folk tale or a novel set in the countryside in the prewar era. おっとう and おっかあ are almost the same. According to Google, there seems to be a few people who still use おとう/おかあ in some rural area, but I have never met them in reality.