magamo Wrote:What? This is the first time ever I've heard ちち called more formal than とうさん. After all, chichi is just the kanji, 父. とうさん is the same, but with a honorary suffix. おとうさん adds the honorary prefix. I can't imagine how 父 could possibly be more formal than 御父さん.lanval Wrote:Can someone explain to me the difference between ちちおや , ちち and とうさん ? とうさん is for other people's, ちち for the own father if I remember correctly, but ちちおや ?ちちおや and ちち are often interchangeable. とうさん is a friendly word for "father" and slightly more informal than おとうさん. All these words can refer to either your own or another person's father. ちち and ちちおや are more formal than おとうさん and とうさん.
Sometimes ちち means the Father, i.e., God. Also, noun+の+ちち can have different meanings just like "father" in English. For example, バッハは音楽の父だと呼ばれている means "Bach is called the father of music." ちちおや and other synonyms don't have this kind of usage.
(Of course, you're the native speaker so I'm not calling you wrong or anything. I'm just extremely surprised.)
Also, let's not forget おやじ which is a very informal word used for your own father, often used by teens, the female version (of mother that is) being おふくろ.