In phonetics, ejective consonants are usually voiceless consonants that are pronounced with a glottalic egressive airstream. In the phonology of a particular language, ejectives may contrast with aspirated, voiced and tenuis consonants. Some languages have glottalized sonorants with creaky voice that pattern with ejectives phonologically, and other languages have ejectives that pattern with implosives, which has led to phonologists positing a phonological class of glottalic consonants, which includes ejectives.
In producing an ejective, the stylohyoid muscle and digastric muscle contract, causing the hyoid bone and the connected glottis to raise, and the forward articulation (at the velum in the case of [kʼ]) is held, raising air pressure greatly in the mouth so when the oral articulators separate, there is a dramatic burst of air. The Adam's apple may be seen moving when the sound is pronounced. In the languages in which they are more obvious, ejectives are often described as sounding like “spat” consonants, but ejectives are often quite weak. In some contexts and in some languages, they are easy to mistake for tenuis or even voiced stops. These weakly ejective articulations are sometimes called intermediates in older American linguistic literature and are notated with different phonetic symbols: C! = strongly ejective, Cʼ = weakly ejective. Strong and weak ejectives have not been found to be contrastive in any natural language.
In strict, technical terms, ejectives are glottalic egressive consonants. The most common ejective is [kʼ] even if it is more difficult to produce than other ejectives like [tʼ] or [pʼ] because the auditory distinction between [kʼ] and [k] is greater than with other ejectives and voiceless consonants of the same place of articulation. In proportion to the frequency of uvular consonants, [qʼ] is even more common, as would be expected from the very small oral cavity used to pronounce a voiceless uvular stop. [pʼ], on the other hand, is quite rare.