m. c. de marco: The Accidental Conlanger
De, Deb, Deba: Speedtalk and Philosophical Languages
Among the linguistic options available to the accidental conlanger is an approach I like to think of as the method of exhaustion. Construct your fictional language in a systematic, exhaustive way and you will end up with something like Robert Heinlein’s Speedtalk or a philosophical language.
Speedtalk, with the endearing naivete so common to conlangs in fiction, assigns a phoneme to every “word,” so that a sentence in Speedtalk is as short as a word in a real language. Neither Speedtalk nor any human language has enough phonemes to make this work, but here is an attempt to fix up Speedtalk.
Philosophical languages, while also ultimately impractical, take a superficially more promising approach by building up words of the usual length out of fragments (usually, but not always, individual phonemes) which represent more general concepts. The outcome is half-language, half library catalog. The classic example is John Wilkes' philosophical language, the philosophical flaws of which were pointed out by Jorge Luis Borges.
The linguistic flaw is the same as Speedtalk; words (or sentences) are not sufficiently differentiated phonetically to make the language comprehensible in use. It’s possible to get around this issue, but only by making the philosophical units larger and thus unwieldy. This can be a good approach for a naming language; see, for example, The Collier Classification System for Very Small Objects (via @thatwhichmatter).
Though the urge to create philosophical languages is common among conlangers, writers are urged to avoid them due to the difficulty of constructing enough of the language to be useful. They may be useful for small semantic domains, as in the Collier Classification, or for making claims about an alien language that you do not intend to back up with a corpus. (Heinlein wrote only a handful of “sentences” of Speedtalk.) But humans do not talk this way.