This glossary gives a general overview of the various

sound laws A sound change, in historical linguistics, is a change in the pronunciation of a language. A sound change can involve the replacement of one speech sound (or, more generally, one phonetic feature value) by a different one (called phonetic chang ...

that have been formulated by linguists for the various

Indo-European languages The Indo-European languages are a language family native to the overwhelming majority of Europe, the Iranian plateau, and the northern Indian subcontinent. Some European languages of this family, English, French, Portuguese, Russian, Dutc ...

. A concise description is given for each rule; more details are given in their articles.

Within Proto-Indo-European or multiple branches

Balto-Slavic

Baltic

Slavic

Germanic

Indo-Iranian

In all words or word-groups of four or more syllables bearing the chief accent on a long syllable, a short unaccented medial vowel was necessarily syncopated, but might be restored by analogy