I found this a novel way of describing voices, using poetic terms. 

Two small children: one voice dactyl, one voice spondee. 

You’ll recall that a spondee, as its own internal rhythm suggests, is a tum-tum beat.  A dactyl is a long foot followed by two hops, something I recall by exaggerating my emphasis in the word ‘DAC-tyl-ic’.  See another example of the dactyl in Leigh Fermor’s comment on Hungarian.

Source: Lawrence Durrell, Reflections on a Marine Venus (London: Faber & Faber, 1960), p. 106

Photo credit: Peggy_Marco at pixabay