I think the l dropping phenomenon which I ve heard even among educated kiwis arises from the fact that in New Zealand English lip rounded vowels are pronounced differently if l follows The vowel in school is a high back vowel while that in scoot is a high central one Similarly the diphthong in coal consists of a middle back vowel gliding into a high back one while that in coat consists of a low to lower mid central vowel gliding into a high central one If the l is dropped the vowel sound still conveys the impression of a following dark l even to the ears of a non l dropping kiwi In these instances l is dropped rather than replaced with w When l follows a non lip rounded vowel l droppers replace it with a high back lip rounded vowel sound It is probably misleading to represent this as w as the consonantal w does not involve the raising of the back of the tongue in NZ English Copey