I am responsible for what I say, not for what you understand.

Speaking carries a duty of care, but only up to a point. The speaker owns the words they chose, how clearly they said them, and the intention behind them. The speaker does not own the private meanings a listener builds from those words, which are shaped by mood, history, and old wounds. The line draws a boundary around what is truly yours to answer for.

It echoes the Stoic habit of separating what is in our control from what is not, and it fits the plain observation from communication theory that a message is completed in the listener's mind, where the speaker cannot follow. No reliable source is known for the saying, which circulates anonymously. It is also easy to misuse. Read carelessly, it becomes an excuse for vagueness or cruelty. Read well, it asks for honest, precise speech and then a calm acceptance of the rest.

Imagine you give a colleague feedback on their report, choosing your words with care and keeping them specific and kind. They still go quiet and seem hurt. You can ask whether they have questions and clarify what you meant, but you need not retract true, carefully put words or keep guessing at what they heard.