Meeussen's rule is a special case of tone reduction. It was first described in Bantu languages, but occurs in analyses of other languages as well, such as Papuan languages.[1] The tonal alternation that it describes is the lowering, in some contexts, of the last tone of a pattern of two adjacent high tones (HH), resulting in the pattern HL. The phenomenon is named after its first observer, the Belgian Bantu specialist A. E. Meeussen (1912–1978). In phonological terms, the phenomenon can be seen as a special case of the obligatory contour principle.
The term "Meeussen's Rule" (the spelling with a capital R is more common) first appeared in a paper by John Goldsmith in 1981.[2][3] It is based on an observation made by Meeussen in his 1963 article on the Tonga verb stating that "in a sequence of determinants, only the first is treated as a determinant".[4] John Goldsmith reformulated that as the rule HH > HL (or, as he expressed it, H → L / H ), which later became well known as Meeussen's rule.[5]
Meeussen's rule is one of a number of processes in Bantu languages by which a series of consecutive high tones is avoided. The processes result in a less tonal, more accentual character in Bantu tone systems and causes a situation in which there tends to be only one tone per word or morpheme.[6]