Pharyngealisation is a secondary feature of phonemes in a language. It refers to a constriction of the pharynx produced at the same time as a phoneme is produced.
Not every language utilises pharyngealisation; English, for instance, neglects it from a phonemic point of view. However, in Russian, the letter l represents two phonemes, one traditionally called palatalised, the other called plain. The "plain" l in Russian is realised as l with pharyngealisation.
Ubykh, another language of Russia, also uses pharyngealisation, possessing 14 pharyngealised consonants.
Arabic also uses phonemic secondary pharyngealisation, with the "emphatic" dental consonants in Arabic actually being pharyngealised.