In some languages pitch is not only melodic but lexical. Tone is the use of pitch patterns to distinguish word meanings or grammatical categories, as in many languages of Africa, East Asia, and the Americas.

Level tones and contour tones combine into language-specific inventories. Tone sandhi rules alter tones in sequence. Orthographies may mark tone with diacritics, numbers, or not at all, creating challenges for literacy and documentation.

Non-tonal languages use pitch mainly for intonation; tonal languages use it for both lexical contrast and intonation. Fieldworkers test minimal pairs that differ only in tone. Mishearing tone can produce entirely different words.

• Pitch used to distinguish meaning
• Includes level and contour tone types
• Subject to sandhi and orthographic decisions
• Lexical in tonal languages, unlike pure intonation