The original Loglan was designed with many ambitious goals. From the
back cover of "Loglan 1, a logical language", the 1975 edition, by Brown:
"Loglan is a language designed to test the Sapir-Whorf hypothesis that
the natural languages limit human thought. It does so by pushing
those limits outward in predictable directions, principally by..." followed
by a list of features, which are summarized by claims that the language
is "transformationally powerful... metaphysically parsimonious...
syntactically unambiguous... semantically non-restrictive... culturally
neutral".
My personal feeling, based on attempts to learn Loglan, and the
experiences of others that I have read about, is that the language is hard
if not impossible to learn and speak naturally. A more recent linguistic
theory is Noam Chomsky's idea of universal grammar, which proposes that
all human tongues are constrained by the wiring of the brain to a small
subset of the potentially imaginable languages. It seems to me that
Loglan (in at least some of its features) may be outside the range of
what the human brain is wired to speak. In this way it can be a test
of Chomsky's idea as well as Whorf's, and I'd say the preliminary data
favors Chomsky.
Hal