Would I answer be Watashi kotaeru?

Answer 1

If you mean "What is the Japanese for 'I answer' ?" it is kotaerimasu.

This is the present form of the verb and can mean "I answer", "you answer", "he answers" "she answers", "we answer", "you all answer" or "they answer".

The Japanese do not often use a word for "I" in normal speech unless they want to specifically emphasise that it is themselves and not someone else doing the answering; your version would literally mean "I will answer". Japanese has a significant tendency to avoid all pronouns most of the time, particularly the personal pronouns - English speakers often make the mistake of trying to translate every English word into Japanese, producing a non-Japanese result.