Speech is a human vocal communication using language. It involves the use of phonetic combinations of vowel and consonant sounds that form the sound of words, and using those words in their semantic context. Speech is the subject of study for linguistics, cognitive science, communication studies, psychology, computer science, speech pathology, otolaryngology, and acoustics. Speech perception refers to the processes by which humans can interpret and understand the sounds used in language. Speech includes articulation, voice, fluency, and rhythm. Articulation refers to how we make speech sounds using the mouth, lips, and tongue, while voice refers to how we use our vocal folds and breath to make sounds. Fluency refers to the rhythm of our speech, and rhythm refers to the way we sometimes repeat sounds or pause while talking.