Pedersen's law

It was originally proposed by Ferdinand de Saussure for Baltic to explain forms such as Lithuanian dùkterį, dùkteres (compare Ancient Greek thugatéra, thugatéres), but was later generalized in 1933 to Balto-Slavic by Pedersen, who then assumed that accentual mobility spread from the consonant-stems to Balto-Slavic eh₂-stems and o-stems.

The term "Pedersen's law" is also applied to later Common Slavic developments in which the stress retraction to prefixes/proclitics can be traced in mobile paradigms, such as Russian ná vodu 'onto the water', né byl 'was not', pródal 'sold', and póvod 'rein'.

Proto-Indo-European *poh₂imń̥ ~ *poh₂imén 'shepherd' (Ancient Greek poimḗn, accusative singular poiména) > Lithuanian piemuõ, acc.

Proto-Indo-European *gʰolHwéh₂ with Balto-Slavic semantics of 'head' > Lithuanian galvà (with accusative singular gálvą), Russian golová (acc.

Later the retraction of stress spread by analogy to non-consonant stems in case-forms where Pedersen's law applied (commonly termed "barytonesis").