tonal contrast

Sources

• BOUQUIAUX & THOMAS 1992 [trans.] 109 (tone contrast)

  BOUQUIAUX, Luc & THOMAS, Jacqueline M.C. (eds.) (1992 [trans.]) Studying and Describing Unwritten Languages. Trans. By James Roberts.  Dallas : SIL. 

• Ducrot & Todorov 1979[trans.] 179 (tonal opposition)

  DUCROT, Oswald and TODOROV, Tzvetan. (1979 [trans.]) Encyclopedic Dictionary of the Sciences of Language. Trans. by Catherine Porter. Baltimore: Johns Hopkins University Press. 

• WELMERS 1973 77, 107

  WELMERS, William E. (1973) African Language Structures. Berkeley: University of California Press.