The Spanish word 'interlocutor' comes from Latin and is made up of three parts: 'inter-' meaning 'between', 'loqui' meaning 'to speak', and '-tor', which is an agent suffix indicating the person who does something. These elements combined in Latin to form 'interlocutor', literally meaning 'one who speaks between others'. In Spanish, the meaning evolved slightly to refer to 'one who participates in a conversation' more generally.

Some related Spanish words include 'locuaz' (talkative), 'locución' (phrase or expression), and 'elocuente' (eloquent). All these words share the Latin root 'loqui' (to speak). While 'interlocutor' specifically refers to a conversation participant, these related words all deal with different aspects of speaking and communication.

English speakers might recognize the connection to words like 'interlocutor', which is the same word in English with the same meaning, as well as 'elocution' (the skill of clear and expressive speech), 'eloquent' (fluent or persuasive speaking), and 'loquacious' (tending to talk a great deal). All these words share the Latin root 'loqui'. The prefix 'inter-' is also familiar from many English words like 'international', 'interact', and 'intervene', always carrying the sense of 'between' or 'among'.