The term collocutor is not used very often in English and is mostly replaced by the more common term "interlocutor." The two words are interchangeable and refer to a person who participates in a dialogue or conversation with another person or group of people. Other synonyms for the term could be conversationalist, speaker, talker, or even communication partner. The use of these synonyms may vary depending on the context in which they are used, but they all serve to describe someone who engages in meaningful conversation and can contribute to a dialogue in a constructive way.