Musical phrasing is the method by which a musician shapes a sequence of notes in a passage of music to allow expression, much like when speaking English a phrase may be written identically but may be spoken differently, and is named for the interpretation of small units of time known as phrases (half of a period). A musician accomplishes this by interpreting the music—from memory or sheet music—by altering tone, tempo, dynamics, articulation, inflection, and other characteristics. Phrasing can emphasise a concept in the music or a message in the lyrics, or it can digress from the composer's intention, aspects of which are commonly indicated in musical notation called phrase marks or phrase markings. For example, accelerating the tempo or prolonging a note may add tension.