Proto-Indo-European accent
Proto-Indo-European accent refers to the theoretical accentual (stress) system of the hypothetical Proto-Indo-European language. == Description == Proto-Indo-European (PIE) is usually reconstructed as having a "pitch accent" system where one syllable of each phonological word had a higher pitch than the other syllables.
Source: Wikipedia — Proto-Indo-European accent (CC BY-SA 4.0)