Reibelaut

Reibelaut is a term used in phonetics, particularly in German-language literature, to describe a class of consonants produced with audible friction of the airstream. The word literally means "friction sound." In many definitions, Reibelaut corresponds to the set of sibilants, including fricatives and affricates, that create a hissing or rushing noise as air passes through a narrowed constriction.

Most commonly, Reibelauten in the phonetic inventory are voiceless and voiced sibilants such as [s], [z], and the postalveolar or alveolo-palatal varieties like [ʃ] and [ʒ], along with their affricate counterparts such as [t͡s] and [d͡z]. The places of articulation typically include dental, alveolar, and postalveolar regions, though languages may differ in exact realization. The defining feature is the presence of frication noise rather than a complete stop or open airflow.

In German phonology, the term helps distinguish these noisy consonants from other manners of articulation, such as stops or nasals. The concept is sometimes noted in older or regional literature under terms like Zischlaut (hissing sound), though Zischlaut is more commonly used in broader descriptions of sibilants. Across languages, Reibelauten are analyzed for their articulatory properties (place and manner of articulation, voicing) and their phonological roles, including contrasts, assimilation, and allophony.

Overall, Reibelaut denotes the subset of consonants characterized by frictional noise in the airstream, primarily encompassing sibilant fricatives and affricates within a given language’s phonemic system.