Ideally, a listener (reader) should be able to identify the part of speech of a word immediately
I'm not so sure.
Knowing a word's part of speech is of limited use if you don't know its actual meaning. Learning a word's meaning generally tells you its part of speech too. If by some chance you have an idea of a word's meaning but not its part of speech (because of ambiguities as with "ship", or because you worked out what kind of thing it has to mean etymologically), that's often enough to work out what's going on anyway. What's the real benefit here of making the part of speech more visible? It sounds nice, but when does it actually help much?
It doesn't seem unreasonable to ask that every important case in which a preposition must be used should correspond to a distinct word.
I'm not so sure.
Inside view: there are really quite a lot of preposition-functions, and prepositions want to be short words, so if we insist on a separate preposition for every preposition-function we'll need to allocate a lot of short words for them. Short words are a scarce resource. The language will have to be clumsier in other ways.
Outside view: every language I know enough about (admittedly a small subset of the world's languages) overloads its prepositions. That's got to be some evidence that doing so isn't a terrible idea.
Outside view: every language I know enough about (admittedly a small subset of the world's languages) overloads its prepositions. That's got to be some evidence that doing so isn't a terrible idea.
I think it's evidence that it's not easy for prepositions to get added through natural language evolution. It much easier to add new verbs, adjectives and nouns.
Short words are a scarce resource.
While that's true when it comes to conlang design, if you look at English there's plenty of open space of short words. A lot of two letter combinations that are possible with English phonetics aren't valid English words.
I'm working on a conlang (constructed language) and would like some input from the Less Wrong community. One of the goals is to investigate the old Sapir-Whorf hypothesis regarding language affecting cognition. Does anyone here have any ideas regarding linguistic mechanisms that would encourage more rational thinking, apart from those that are present in the oft-discussed conlangs e-prime, loglan, and its offshoot lojban? Or perhaps mechanisms that are used in one of those conlangs, but might be buried too deeply for a person such as myself, who only has superficial knowledge about them, to have recognized? Any input is welcomed, from other conlangs to crazy ideas.