An Encyclopedia of Phonological Features

Phonological features are the smallest units of language, properties of speech both within and beyond the segment. Also known as distinctive features, phonological features cross-classify the sounds of a language, revealing groups of sounds that pattern together. For example, the English sounds /p, t, k/ share properties of completely blocking continuous airflow while simultaneously lacking vibration in the vocal folds. Features, whose names are usually enclosed within brackets, were first conceived as binary oppositions, so among English sounds, this set would be [-continuant] and [-voice]. English utilizes this set of sounds for rules such as aspiration (adding a puff of air at the beginning of a stressed syllable).

This encyclopedia allows the user to look up entries to learn more about particular features, from their earliest formulation in 1949 with six features, to more complicated proposals of three dozen or more features. Some features were proposed and then abandoned, and those proposals are chronicled alongside features that have stood the test of time. But with these three dozen or so features, linguists can describe all of the sounds of the 7,000 languages in the world.