구어(gu-eo, gueo)
Informal, natural spoken language used in everyday situations
When to use
casual talk, friendly context, informal expression
The nuance
Use 구어 mainly in casual, everyday speech or informal contexts; it contrasts with written or formal language and is unsuitable for official writing or speeches.
말(mal)
The act of speaking or the words themselves used to express thoughts or feelings
When to use
general speech act, words themselves, expressing thoughts
The nuance
말 is a broad, general term covering the act of speaking or words themselves, used in various contexts without specific restrictions.
대화(dae-hwa, daehwa)
Interactive communication between two or more people
When to use
interactive communication, two or more participants, Q&A exchange
The nuance
대화 refers to interactive communication involving at least two participants; it cannot describe monologues or self-talk.