Generally you're using language "correctly" when the vast majority of people understand what you were trying to communicate. In that way and in that context it

Generally you're using language "correctly" when the vast majority of people understand what you were trying to communicate. In that way and in that context it's a "passable" statement. Don't view everyday life and sentences through the narrow lens of mathematics/logic. If you're lucky that'll make for some dinner conversation, if you're unlucky you'll just be annoying. "I know this must be leaking because it smells." is fine in an everyday context, even if not strictly and always true.