Dialogue and Think-Aloud
A dialogue is any conversation between two or more people, often intended to resolve a problem by negotiation. Each person’s ideas are tested against the understanding of the other person(s), and (ideally) weak or false ideas are eliminated while strong ideas are agreed between the pair or group. Dialogue can be between teacher and student or between student and student (and, these days, between a student and various forms of AI).
Dialogue is typically between two or more people, but more subtle forms also exist. When someone talks to themselves as they try to solve a problem, that articulation of their thought process arguably constitutes an internal dialogue.
'Think-aloud' is easy to define – if you think aloud, you deliberately express your thoughts immediately as they occur to you, rather than thinking first and then speaking. You narrate your thought processes in their entirety as they are happening. You might do this while you are actually in the process of trying to solve a problem. This gives an insight into how your mind is working, how you are going about problem-solving, which lines of thought lead to positive outcomes and which are less successful. Of course, pairs and groups can do think-alouds together.
Dialogue and Think-Aloud: Reviews of Research Evidence