Woisika is spoken in the center of the island of
Alor, Nusa Tenggara Timur, Indonesia. Because Stokhof
(1979) places 'w' on his chart of symbols in the
labiodental column it is assumed the sound is labiodental.
The vowels are described by Stokhof as divided into
"tense" and "lax" sets. The "tense" vowels are usually
lower, more peripheral and longer than the "lax" vowels
and also are lower in pitch. "Lax" vowels, except for /a/,
are more common than their nearest "tense" counterparts.
The features available in UPSID require some compromises
in vowel representation. Retracted front high and fronted
back high vowels are represented here as central, although
Stokhof marks them as halfway between center and
periphery. Similarly, a retracted central low unrounded
vowel is shown as back here. Palatograms included in the
book show clearly dental articulation for /t, d, n/ etc.
but Stokhof indicates variation to alveolar place.

Stokhof, W.A.L. 1979. Woisika II: Phonemics. (Pacific
Linguistics, Series B, No. 59). Australian National
University, Canberra.