Inflection refers to the ups and downs of a language. Even if you can’t understand Italian yet, the inflection in your professor’s voice should tip you off to whether she's asking a question, giving a command, or making a joke.
What began in the 1500s as a noun of action spelled inflexion has since evolved into inflection, a word with grammatical connotation. Inflection most often refers to the pitch and tone patterns in a person’s speech: where the voice rises and falls. But inflection also describes a departure from a normal or straight course. When you change, or bend, the course of a soccer ball by bouncing it off another person, that’s an example of inflection.