division of the Indo-European
family includes the following branches: Indo-Iranian
, plus a number of barely documented extinct languages, such as Thracian and Dacian (see: Indo-European languages
). All those languages show the characteristic change of the so-called Proto-Indo-European
) into affricate
consonants articulated in the front of the mouth. For example, *k^
became Sanskrit s′
and Armenian s
, Lithuanian s^
, Albanian th
, etc. At the same time, the protolanguage velars
(*k, *g, *gh
) and labio-velars (*kw
) merged in the Satem group, the latter losing their accompanying lip-rounding.
By contrast, in the remainder of the Indo-European family (the so-called Centum languages), palato-velars lost their palatal component and merged with plain velars, while labio-velars remained distinct.
The Satem shift is conveniently illustrated with the word for '100', Proto-Indo-European *k^mtom, which became e.g. Avestan satem (hence the name of the group), Lithuanian s^imtas, etc., as contrasted with Latin centum (pron. [kentum]), English hund(red)- (with /h/ from earlier *k, see Grimm's law), Greek (he)katon, Welsh cant, etc.
The Satem group is a paraphyletic group and thus not a phylogenetic unit.