Proto-Indo-European accent

Proto-Indo-European accent refers to the accentual system of Proto-Indo-European language.

Proto-Indo-European (PIE) is usually reconstructed as having had variable lexical stress: the placement of the stress in a word (the accent) was not predictable by its phonological rules. Stressed syllables received a higher pitch than unstressed ones so PIE is often said to have had pitch accent.

(That must not be confused with the other meaning of the term "pitch accent", which refers to a system of one or two syllables per word having one of at least two unpredictable tones, and the tones of any other syllables being predictable.)

PIE accent could be mobile so it could change place throughout the inflectional paradigm. That occurred also Vedic Sanskrit and Ancient Greek, as in the declension of athematic nouns,

or in the conjugation of athematic verbs (compare Sanskrit root present first-person sg. émi, first-person plural imás).

Otherwise, the accent was placed at the same syllable throughout the inflection. Nouns are divided into barytones if they are accented on the first syllable and oxytones if that are accented on the last syllable:

PIE accent was also free so it could stand on any syllable in a word, which was faithfully reflected in the Vedic Sanskrit accent (the later Classical Sanskrit had a predictable accent):

As one can see, the placement of the reconstructed PIE accent is reflected in Vedic Sanskrit basically intact. According to the reflex of the PIE accent, Indo-European languages are divided into those with free accent preserved, either directly or indirectly, and those with fixed (or bound) accent. Free accent is preserved in Vedic Sanskrit (of modern Indo-Iranian languages, according to some and Pashto), Ancient Greek, Balto-Slavic and Anatolian. In Proto-Germanic, free accent was retained long enough for Verner's Law to be dependent on it, but later, stress was shifted to the first syllable of the word.

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