This is an African feature which is found in New Guinea- implies that this feature has been preserved from the initial southern route.
<!--QuoteBegin-->QUOTE<!--QuoteEBegin-->http://en.wikipedia.org/wiki/Labial-velar_consonant
Truly doubly articulated labial-velars occur as plosives and nasal stops in the majority of languages in <b>West and Central Africa, </b>and are relatively common in the <b>eastern end of New Guinea. </b>They include <b>[kÍ¡p, É¡Í¡b, ÅÍ¡m].</b> The Yélî Dnye language of Rossel Island, Papua New Guinea, has both labial-velars and labial-alveolar consonants. Labial velar unvoiced plosives and nasals also occur in Vietnamese, albeit only at the end of words.<!--QuoteEnd--><!--QuoteEEnd-->
<!--QuoteBegin-->QUOTE<!--QuoteEBegin-->http://en.wikipedia.org/wiki/Labial-velar_consonant
Truly doubly articulated labial-velars occur as plosives and nasal stops in the majority of languages in <b>West and Central Africa, </b>and are relatively common in the <b>eastern end of New Guinea. </b>They include <b>[kÍ¡p, É¡Í¡b, ÅÍ¡m].</b> The Yélî Dnye language of Rossel Island, Papua New Guinea, has both labial-velars and labial-alveolar consonants. Labial velar unvoiced plosives and nasals also occur in Vietnamese, albeit only at the end of words.<!--QuoteEnd--><!--QuoteEEnd-->