From: G&P
Message: 61845
Date: 2008-12-03
> I lean more toward the
idea
> of only two
series, velars and labiovelars.
If you mean for your conlang, you can do whatever you like. If you mean for PIE, you would have trouble describing the attested pattern of language cognates with only two, and indeed, describing the hints of three within individual languages, such as Anatolian, Albanian, Armenian and so on.
Peter