H₂e-conjugation theory

The *h₂e-conjugation theory adds a third conjugation to the two generally accepted conjugations of the Proto-Indo-European language (PIE), the thematic and athematic conjugations.

The symbol *h₂ refers to a particular example of a class of sounds known as "laryngeals" in the theory of PIE linguistics; it is believed to have been a pharyngeal fricative such as [ħ] or [ʕ]; the uvular fricative [χ] or the voiceless velar fricative [x] have also been suggested.