Origins
The noun 'soliloquy' entered English in the early seventeenth century from Late Latin 'sōliloquium' (a talking to oneself), a compound of Latin 'sōlus' (alone) and 'loquī' (to speak). The word has an unusually precise origin: it was coined by Saint Augustine of Hippo around 386 CE for the title of his work 'Soliloquia,' a philosophical dialogue between himself and Reason. Augustine acknowledged the novelty of the word, calling it perhaps ugly but fit for its purpose.
Augustine's 'Soliloquia' is not a soliloquy in the theatrical sense — it is a dialogue, albeit an internal one between the author and a personified abstraction. But Augustine's coinage captured something important: the idea that speaking to oneself is a distinct mode of discourse, different from speaking to others. In conversation, we shape our words for a listener. In soliloquy, we speak as we think — or rather, we think by speaking. The soliloquy makes the interior life audible.
In English drama, the soliloquy became the principal device for revealing a character's inner thoughts to the audience. Elizabethan and Jacobean playwrights used it extensively. Shakespeare's soliloquies are among the most famous passages in English literature. Hamlet's 'To be, or not to be' is a meditation on existence and death. Macbeth's 'Tomorrow, and tomorrow, and tomorrow' is a nihilistic reflection on the meaninglessness of life. Richard III's opening soliloquy ('Now is the winter of our discontent') establishes the character as a self-aware villain who takes the audience into his confidence.
Development
The theatrical soliloquy depends on a convention: the audience agrees to believe that the character is alone and speaking truthfully. Unlike dialogue, where characters may lie, dissemble, or perform for each other, the soliloquy is understood to represent unmediated thought. When Hamlet soliloquizes, the audience trusts that he is revealing what he truly thinks and feels. This convention gives the soliloquy extraordinary dramatic power — it creates intimacy between the character and the audience that no dialogue can match.
The distinction between soliloquy and monologue is often debated. Strictly, a soliloquy is spoken by a character who is alone (or believes themselves to be alone), while a monologue is a long speech delivered to other characters. In practice, the terms overlap. Hamlet's 'To be, or not to be' is traditionally called a soliloquy, but in some stagings, Hamlet is aware of being overheard. Mark Antony's 'Friends, Romans, countrymen' is a monologue — a speech to a crowd — not a soliloquy. The difference is one of audience: soliloquy addresses the self (and through the self, the theater audience); monologue addresses other characters.
After the Restoration, English drama moved away from the soliloquy. The rise of naturalism in the nineteenth century made the convention seem artificial — real people do not stand alone in rooms delivering articulate speeches about their feelings. Henrik Ibsen, Anton Chekhov, and their successors developed subtler techniques for revealing character: subtext, silence, the gap between what characters say and what they mean. The soliloquy seemed to belong to an older, more rhetorical theater.
Modern Usage
But the soliloquy has never entirely disappeared. Modern and contemporary drama periodically rediscovers it. Bertolt Brecht used direct address to the audience (a form of soliloquy) as part of his 'epic theater' technique. Samuel Beckett's 'Not I' (1972) is essentially a fifteen-minute soliloquy delivered by a disembodied mouth. In film, the voice-over narration functions as a kind of soliloquy — a character's inner thoughts made audible to the audience.
The psychological reality of soliloquy — talking to oneself — is more common than social convention admits. Research in psychology has shown that self-directed speech ('private speech' or 'self-talk') plays an important role in cognitive development, problem-solving, and emotional regulation. Children routinely talk to themselves while playing or working through problems, and adults do so more often than they typically acknowledge. The soliloquy, far from being a theatrical artifice, reflects a genuine feature of human cognition: we think, in part, by talking to ourselves.
The German equivalent, 'Selbstgespräch' (self-conversation), is more transparent than the Latinate English word — it names the activity plainly. French 'soliloque' and Italian 'soliloquio' preserve the Latin compound directly. In each language, the word occupies the same position: a learned term for a phenomenon that is both theatrical convention and psychological reality.