English has 44 phonemes or word sounds that make up the language. Phonemes include 19 consonants, 7 digraphs, 5 'r-controlled' sounds, 5 long vowels, 5 short vowels, 2 'oo' sounds, and 2 diphthongs. Phonetics is the scientific study of speech sounds, including how they are produced, perceived, and their physical properties. It has three branches: articulatory phonetics studies sound production, acoustic phonetics studies physical properties, and auditory phonetics studies perception. Speech sounds are organized into phonetic features, phonemes, allophones, words, utterances, and longer stretches of speech.