Loglan is a logical constructed language originally designed for linguistic research, particularly for investigating the Sapir–Whorf hypothesis.

Brown founded The Loglan Institute (TLI) to develop the language and other applications of it.

He always considered the language an incomplete research project, and although he released many publications about its design, he continued to claim legal restrictions on its use.

The grammar was intended to be small enough to be teachable and manageable, yet complex enough to allow people to think and converse in the language.

Brown intended Loglan to be as culturally neutral as possible and metaphysically parsimonious, which means that obligatory categories are kept to a minimum.

Unlike in English and many other languages, this structure word is required; an unadorned name cannot be used as an argument.

So "Le sadji matma pa vedma" means "The wise mother sold", and "Le matma vedma pa sadji" means "The motherly seller was wise".

So "Le matma pa sadji vedma" means "The mother wisely sold".

Thus Loglan can distinguish between the many possible meanings of the ambiguous English phrase "the pretty little girls' school", as in these examples: Predicates can be modified to indicate the time at which something occurred (English tense) with the optional structure words "na" (present), "pa" (past) and "fa" (future).

So "Le matma ga vedma" means "The mother sells (at some unspecified time in the past, present or future)".

Compare the sentences Free variables apply equally to people of any gender and inanimate objects; there is no distinction similar to that between English "he", "she" and "it".

Loglan has several sets of conjunctions to express the fourteen possible logical connectives.

The word is chosen to make it easy for a Loglan speaker to see that "A noa B" is logically equivalent to "no A a B".

Brown argues that it is thus easier in Loglan than in English to see that two sentences like these are different ways of saying the same thing: The conjunction "a" expresses the inclusive-or relation; that is, one of the two alternatives is true, or possibly both.

For example, "Le negda ga nigro ze blabi" means "The egg is black-and-white".

On the other hand, "Le negda ga nigro e blabi" would make the claim that "The egg is black and (it is also) white".

There is a set of words used for expressing attitudes about what one is saying, which convey conviction, intention, obligation and emotion.

For example: Loglan was mentioned in a couple of science fiction works: Robert A. Heinlein's well-known books, including The Moon Is a Harsh Mistress and The Number of the Beast, Robert Rimmer's utopian book Love Me Tomorrow (1978) and Stanisław Lem novel His Master's Voice.

Archival material related to the creation and teaching of Loglan, including flashcards and grammar explanations, can be found in the Faith Rich Papers, located at Chicago Public Library Special Collections, Chicago, Illinois.