mi wile ala ante e toki pona. mi wile e ni taso: jan li ken lukin pona e nasin nimi pi toki pona.
1. The 'jan li pana e sitelen tawa mi' = " A guy gave me a picture" or "I guy showed my movie" problem. Nothing in writing distinguishes that 'tawa' as modifier or preposition. There is probably a difference in speech, though. I suggest that we import that vocal suprasegmental (juncture, in this case, I suppose) to something in our writing: a comma before the preposition: 'sitelen, tawa mi' = "a picture to me" v 'sitelen tawa mi' = "my movie"
2. While on prepositional phrases, let's officially allow them to modify noun phrases. but, since they are going to be at least two words long and grouped as a unit, lets offset them with 'pi' (OK, this is probably a change, but ...): 'jan suli pi tan ma lili Teja' "a big man from Texas"
3. And while we are on 'pi,' what can we do about structures of the form: a pi b c d, where d can modify either b c or a pi b c? Commas would only add to confusion here. One partial suggestioon is to move a modifier a pi b c up to modify a directly wherever possible: a d pi b c. The other advise is the standard "don't use such complex phrases to begin with," but doesn't get us far when we need the complexity.
4. 'tenpo la' structures (probably all 'la' structures) Here I have no suggestions at all, merely a plea for some regularizations. We seem to have usually managed so far; how did we do it and what generalizations can be drawn from that? Here are some apparent agreed cases (note that they don't fit into patterns very well):
tenpo mute/lili often/rarely
tenpo suli for a long time ("a short time" would apparently be 'tenpo lili' again)
tenpo pini/kama in thepast/future
tenpo pini mute a long time ago (or maybe 'tenpo mute pini,' which might also mean "after a long time")
at a time (or event)
for a time (during an even)
5. "about" for the topic of a talk, thought, etc. (toki, sona, pilin, maybe kute, lukin, other?) So far at least the following have been tried:
toki (pi) A ('pi' when A is two or more words, as it usually is)
toki e ijo (pi) A
sike(calque)/ lon (calque)/ tawa (because it's tried for everything) A
The 'ijo' solution does the least damage to common tp, the 'toki pi' solution is not much worse (though it was suggested long ago for "in language A"), none of the preps seem right at first glance.+