D: rehashing my earlier blogs (yes this is a self-referring document) in summary:
1) English requires 1-2-3000 words for basic-medium-advanced literacy level writing
2) Chinese, 2-3-5000ish symbols.
3) Esperanto, 500-1-2000? They do have c. 10,000 roots now.
D: my Decimese.
Can I reduce basic-literacy core vocabulary to 250?
The key here is the generation of a special core vocabulary PRIOR to closed class function words. In turn, the function words are then then derived as compound composites of a space/time/logic/ethic/math (acronym... SMELT? <:).
English has about 300 closed class function words. But if we look at them, and 'reduce them to their alchemical essential salts', there are fewer concepts.
Alchemy? Let me explain. Behind our English vocabulary is a few compounded concepts with variations. Overtly indicating this amounts to words that contain, and can be unpacked into, the actual definition for the word.
Take, for example, this/that, these/those. These are near/far referent, single/plural. Once we have nailed down these elemental aspects, they can be re-used for the rest of the closed class words also. For example, single/plural pronouns. I/we, you/youz, he/she/it and they.
Keep in mind that many core noun/adjective/adverbs are also derived in Decimese from these same elements. See the prime number naming convention, for example.
Indicated 'towards' and above and such from dimensional names is simple enough.
D: are prepositions that brief in English?
D: but then
* according to
* ahead of
* aside from
* because of
* close to
* due to
* as far as
* as well as
* by means of
* in accordance with
* in addition to
Not fully grammaticalised
 Preposition-like modifiers of quantified noun phrases
* apart by
* ago as in "five years ago", sometimes (wrongly) considered an adverb rather than a postposition
* apart as in "this apart", also used prepositionally ("apart from this")
* aside as in "such examples aside", also used prepositionally ("aside from such examples")
* away as in "five light years away", sometimes (wrongly) considered an adverb or an adjective rather than a postposition
* hence as in "five years hence", sometimes considered an adverb rather than a postposition
* notwithstanding also used prepositionally
* on as in "five years on", also used prepositionally
* through as in "the whole night through", also used prepositionally
* withal archaic as a postposition meaning with
D: yes I can. I can use 250 words to
1) define key SMELT concepts in Decimese
2) make the closed class function words, with options expand beyond the English selection
3) a decent repertoire of basic vocabulary.
And I can do so with palatable phoneme selection and syllable rules.
With FOUR indications to parse word boundaries.
Heavily compatible with lip-reading.
And do so with considerable brevity, via consonant clusters to create binary/trinary concept subsets.
Forget 'it works' and 'good enough'.
How about it works very well indeed. And it is so much more than just good enough...