slit-log drum, bombalom

System employing slit-log drums used by the Balante people of Guinea-Bissau, described in Wilson (1963) along with surrogates of several related Bak languages and Sua. The instrument itself (bombalom in Portuguese) is several feet long and elevated on a thick pile of straw. It is beaten with two sticks over a foot in length, producing two pitches “several tones apart” (807). The language, Balanta, has H and L tones, root-initial stress, and contrastive vowel length. In the surrogate system, the H and L tones correspond to high and low pitches. Stressed syllables are encoded with exaggerated strikes: unstressed syllables are variably encoded as mere “light taps” (812). Vowel length is represented by the interval between strikes, wherein long vowels are “followed by a slightly lengthened interval” (812). Enphrasing is employed for rote utterances, but some productive variation is possible: “sentences likely to be needed are memorized… This is not to say, however, that the sentences used are immutable”, and variations are possible (810-11).Content includes long-distance communication, announcements of deaths, ritual practices at funerals, and specific drum names.

Wilson (1963)