Luwian (ˈluːwiən), sometimes known as Luvian or Luish, is an ancient language, or group of languages, within the Anatolian branch of the Indo-European language family. The ethnonym Luwian comes from Luwiya (also spelled Luwia or Luvia) – the name of the region in which the Luwians lived. Luwiya is attested, for example, in the Hittite laws.
The two varieties of Proto-Luwian or Luwian (in the narrow sense of these names) are known after the scripts in which they were written: Cuneiform Luwian (CLuwian) and Hieroglyphic Luwian (HLuwian). There is no consensus as to whether these were a single language or two closely related languages.
Anatolian languages
Several other Anatolian languages – particularly Carian, Lycian, and Milyan (also known as Lycian B or Lycian II) – are now usually identified as related to Luwian – and as mutually connected more closely than other constituents of the Anatolian branch. This suggests that these languages formed a sub-branch within Anatolian. Some linguists follow Craig Melchert in referring to this broader group as Luwic, whereas others refer to the "Luwian group" (and, in that sense, "Luwian" may mean several distinct languages). Likewise, Proto-Luwian may mean the common ancestor of the whole group, or just the ancestor of Luwian (normally, under tree-naming conventions, were the branch to be called Luwic, its ancestor should be known as Proto-Luwic or Common Luwic; in practice, such names are seldom used). Luwic or Luwian (in the broad sense of the term), is one of three major sub-branches of Anatolian, alongside Hittite and Palaic.
As Luwian has numerous archaisms, it is regarded as important to the study of Indo-European languages (IE) in general, the other Anatolian languages, and the Bronze Age Aegean. These archaisms are often regarded as supporting the view that the Proto-Indo-European language (PIE) had three distinct sets of velar consonants: plain velars, palatovelars, and labiovelars. For Melchert, PIE → Luwian z (probably [ts]); → k; and → ku (probably [kw]).