section_path: Evolution/Sound changes
section_name: Sound changes
paragraph_text: Sound changes
  
  As the Proto-Indo-European (PIE) language broke up, its sound system diverged as well, changing according to various sound laws evidenced in the daughter languages.
  
  PIE is normally reconstructed with a complex system of 15 stop consonants, including an unusual three-way phonation (voicing) distinction between voiceless, voiced and " voiced aspirated " (i.e. breathy voiced) stops, and a three-way distinction among velar consonants (k -type sounds) between "palatal" ḱ ǵ ǵh, "plain velar" k g gh and labiovelar kʷ gʷ gʷh. (The correctness of the terms palatal and plain velar is disputed; see Proto-Indo-European phonology.) All daughter languages have reduced the number of distinctions among these sounds, often in divergent ways.
  
  As an example, in English, one of the Germanic languages, the following are some of the major changes that happened:
  
  None of the daughter-language families (except possibly Anatolian, particularly Luvian) reflect the plain velar stops differently from the other two series, and there is even a certain amount of dispute whether this series existed at all in PIE. The major distinction between centum and satem languages corresponds to the outcome of the PIE plain velars:
  
  The three-way PIE distinction between voiceless, voiced and voiced aspirated stops is considered extremely unusual from the perspective of linguistic typology —particularly in the existence of voiced aspirated stops without a corresponding series of voiceless aspirated stops. None of the various daughter-language families continue it unchanged, with numerous "solutions" to the apparently unstable PIE situation:
  
  Among the other notable changes affecting consonants are:
  
  The following table shows the basic outcomes of PIE consonants in some of the most important daughter languages for the purposes of reconstruction. For a fuller table, see Indo-European sound laws.