Pitch accent is a tonal system employed in many languages around the world. In a pitch-accented language, there is an accented syllable or mora, the position of which determines the tonal pattern of the whole word (the pitch of each syllable or mora, usually high vs. low) according to some rules.

Ancient Greek had a pitch accent, which later changed into a stress accent (where accented syllables are pronounced more forcefully, as in English, instead of having a higher pitch).

The several dialects of the Japanese language have a pitch accent too, though the position of the accent for given word varies among them. In standard Japanese The accent rules in standard Japanese are presented here as an example:

  1. If the accent is on the first syllable, then the first syllable is high-pitched and the others are low: H-L, H-L-L, etc.
  2. If the accent is on a syllable other than the first, then the first syllable is low, the following syllables are high up to and including the accented one, and the rest of the syllables are low: L-H, L-H-L, L-H-H-L, L-H-H, etc.
  3. If the word doesn't have and accent, the first syllable is low and everything else is high (and this spreads to grammatical particles, usually unaccented, that may attach at the end of the word).