A constructed language which either belongs to the Loglan family (Loglan itself, Lojban,
Gua\spi, Voksigid) or which is recognizably based on logical principles (And Rosta's Livagian).
why don't we just call them all "loglans" since that's a generic term?
Uncontroversially to the LLG and the U.S. courts, perhaps; but for an incentive not to, I refer you to niction — mi'e nitcion
I think it is useful to reserve loglan for members of the Loglan family. — mi'e And.
A related term that is useful but unused is engelang or engilang for "engineered language", which is a little more general than loglang, "based on logical principles". Features like self-segregating morphology are not particularly logical, but typical of an engelang.
-- mi'e And. (...platybau ?)