Indo-European sound laws


As the Proto-Indo-European language broke up, its sound system diverged as well, as evidenced in various sound laws associated with the daughter Indo-European languages.
Especially notable is the palatalization that produced the satem languages, along with the associated ruki sound law. Other notable changes include:
Bartholomae's law in Indo-Iranian, and Sievers's law in Proto-Germanic and various other branches, may or may not have been common Indo-European features. A number of innovations, both phonological and morphological, represent areal features common to the Italic and Celtic languages; among them the development of labiovelars to labial consonants in some Italic and Celtic branches, producing "p-Celtic" and "q-Celtic" languages. Another grouping with many shared areal innovations comprises Greek, Indo-Iranian, and Armenian; among its common phonological innovations are Grassmann's law in Greek and Indo-Iranian, and weakening of pre-vocalic /s/ to /h/ in Greek, Iranian and Armenian.

Consonants

The following table shows the Proto-Indo-European consonants and their reflexes in selected Indo-European daughter languages. Background and further details can be found in various related articles, including Proto-Indo-European phonology, Centum and satem languages, the articles on the various sound laws referred to in the introduction, and the articles on the various IE proto-languages, language groups and language phonologies. For development of the laryngeals and syllabic consonants, see the [|vowels] table below.
Notes for table 1:

Consonant clusters

Proto-Indo-European also had numerous consonant clusters, such as st, ḱs. In most cases in most languages, each consonant in a cluster develops according to the normal development given in the table above. Many consonant clusters, however, show special developments in multiple languages. Some of these are given by the following table :
Notes to Table 2:

Vowels and syllabic consonants

This table shows the Proto-Indo-European vowels and syllabic consonants, and their reflexes in selected Indo-European daughter languages. Background and further details can be found in various related articles, including Proto-Indo-European phonology, the articles on the various sound laws referred to in the introduction, and the articles on the various IE proto-languages, language groups and language phonologies.
Notes:

Examples

See the list of Proto-Indo-European roots hosted at Wiktionary.
, ~ ped-, "foot".
, "three".
, "hundred"
, "raw flesh"

Sound laws within PIE

A few phonological laws can be reconstructed that may have been effective prior to the final breakup of PIE by internal reconstruction.