These words refer to formal or informal vocal exchanges. Conversation and discussion are the most general of these, the former applying mainly to an informal social situation, the latter applying often but not exclusively to a formal or official situation. Conversation , of course, can and does take place at extremely formal affairs, but in this case the word points to incidental exchanges that are not usually the main point of such a gathering. Much more often the tone of the word suggests a relaxed, informal atmosphere, either festive or intimate: a party at which the conversation flowed like wine; a long conversation between the two of them over nightcaps of brandy. Any situation, however, in which two or more people speak to each other at some length and constitute a conversation : He warned her against getting into conversation with other passengers on the train. When discussion indicates formal or arranged situation, it still suggests a free-and easy meeting in which people express their views or sentiments to one another: asking the committee to hold open discussions on the sousing project. The word can specifically point to a period that follows some sort of one-sided presentation, one during which audience reaction is heard: a discussion that was to take place after the play; the general discussion following his speech. When discussion suggests an even more informal situation, the word still differs from conversation in indicating a purposeful approach that limits itself to a given theme, possibly to arrive at conclusions or determine a course of action: family discussions in which each member can openly present his grievances; an innocuous conversation that turned into a heated discussion on police brutality.

Dialogue and colloquy are more formal than the previous words, particularly the latter. Dialogue can refer to speeches in a play or to essays in play form. In the context of conversation, it strictly suggests a two-person exchange, yet this distinction is commonly ignored. The word has recently come to mean arranged discussions among people of dissimilar views: a new dialogue among the Protestant denominations and the Catholic church; a year-round dialogue between labour and management. Colloquy is an extremely formal substitute for discussion , and is typically used of formal situations: an extended colloquy between the witness and the defence counsel. It may refer to a high-level prearranged conference: a continuing colloquy on disarmament at the ambassadorial level. It might also be used humorously to suggest guarded verbal exchanges: my tense colloquy with the customs inspector.

Talk is both relatively informal and very general. It can serve as an informal substitute for conversation , with greater emphasis on intimacy, sincerity and frankness: looking forward to having a good long talk with all his old friends; feeling relieved after their heart-to-heart talk . It can also refer to the substance of conversations or discussions : soirées where the people were interesting and the talk scintillating. The word can also refer informally to a one-sided presentation, as a speech or a lecture: a talk on the housing project. Sometimes, the word is a more general substitute for gossip: indiscreet behaviour that caused talk among the neighbours.

Chat and tête-à-tête are emphatic about the informality and intimacy of the conversation they point to. But chat , most informal of all these words, can refer to two or more people and most strongly suggests light, pleasant, and rambling talk in which personal matters, if touched on, are purused without great intensity: an hour’s chat about the doings of their mutual friends; a chat between mother and daughter about the girl’s growing-up problems. By contrast, tête-à-tête specifically indicates a talk between two people (literally, head-to-head), in which the emphasis is on sincerity and frankness of a confidential, romantic or even conspiratorial sort: seen having a tête-à-tête with her husband’s employer; a tête-à-tête between representative of the two deadlocked candidates.