Not much. Vowel harmony would wreak havoc with the etymology of primitives, since vowels count as much as consonants in the word-building algorithm. But, once that issue were solved, the harmony would be lost in derive predicates, since the vowels carry over to the components and changing them to fit some preestablished pattern would interfere with their identification. Finally, and perhaps most damning, vowel harmony does not affect function words (mostly one syllable) where the problem of noisy channels is the gravest, because of the packed word space and the relatively little use context has in that area (many hard to distinguish words belong to categories that occur in the same frames). So, vowel harmony does not help nearly enough to be worth
pursuing.
On Wednesday, August 20, 2014 10:08 PM, TR NS <transfire@gmail.com> wrote:
On Wednesday, August 20, 2014 5:53:20 PM UTC-4, clifford wrote:
Like most conlangs, Lojban gave virtually no consideration to the noisy room problem -- and has resisted any attempt to deal with the issue since (but then, so has English "talk louder, repeat yourself, ...")
Well considering lojban has just five pure vowel sounds, there is certainly room for playing with vowel harmonies (https://en.wikipedia.org/wiki/Vowel_harmony).