What is pu

[janKipo]

Recursion tends to make for many levels, but that is merely incidental. The essence is the coming back to the same place in the definition again (as the name sorta says).

'tawa', as a verb, always means "move" some how; the question is what moves. With the intransitive, it is the subject; with the transitive, it is the object. The subject brings about the motion of the object, but may do that without any motion on its part (by issuing an order, say, or turning on a magnet).
Your subsequent examples are intransitive and thus not much of a problem -- except for the double 'tawa's, which are merely redundant.
Well, the astronaut version uses 'tawa' for the means, where 'kepeken' seems called for 'kepeken palisa pi suli mute' Oh, you aren't talking about a spaceship! I suspect 'kepeken' is still appropriate, but 'nasin' ought to be here somewhere, for "course" and the like ("vector" isn't quite right since they have direction but not length, but close enough).

Your remark about 'tawa' seems to be the one in use, but is still a bad idea, especially when there are a number of actual and potential preps that no one has tried -- 'nasin' for one (with or without 'lon')

'la' phrases are still conditions, but "condition" has a somewhat different sense. All this needs some work through.

Note that 'tawa mun' also means "go to the moon" which could be confusing.

I am leery of 'pi' with verb phrases, but they should be legal -- just not used much, since other tricks are available -- PP and 'la'.
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[janTe]

There's an ambiguity when a word like "tawa", "poka", or "sama" is used after a noun. Is it a modifier or a preposition? This ambiguity trips me up a lot. (For example, mi pana e tomo tawa sona could mean "I give your car" or "I give a house to you".)

My guess is that "pu" makes clear that the following word is a preposition. I think maybe "I give a house to you" could become *mi pana e tomo pu tawa sona.

This is only a guess. But if it's right, it might become easier to use other words as prepositions. Maybe "nasin" could used for "through" or "across". Maybe "anpa" could be used for "under".

My only "evidence" for this guess is that the French wikipedia claims that "pu" is used to avoid certain ambiguities, and the ambiguity of "pana e tomo tawa sona" was noted a long time ago.

(Though, I'd also be happy for a word that means "block" or "lump" (or "uncarved block"). We have shape words for flat things, and long things, but not for something that's just a lump or a block.)

[janMato]

There's an ambiguity when a word like "tawa", "poka", or "sama" is used after a noun. Is it a modifier or a preposition? This ambiguity trips me up a lot.

If we attack ambiguity too aggressively we'll end up with toki-lojban-pona.

My guess is that "pu" makes clear that the following word is a preposition. I think maybe "I give a house to you" could become *mi pana e tomo pu tawa sona.

If this was the only sample, I'd start using it as a direct-object particle. Except for tawa, it's usually pretty easy to see when a prep phrase is starting, so I'm skeptical. Plus this would rapidly act like a clitic (it would permanently glom onto the 6 official preps, pu-kepeken, pu-lon, pu-poka, pu-sama, pu-tan and not otherwise have any use-- now that I think about it, it would feel like adding 6 more words to the dictionary)

This is only a guess. But if it's right, it might become easier to use other words as prepositions. Maybe "nasin" could used for "through" or "across". Maybe "anpa" could be used for "under".

For pronouns indicating physical locations, we have "lon + pseudo-prep", eg. "lon anpa" http://en.tokipona.org/wiki/Talk:anpa

maybe
? mi pana e tomo lon tawa sina.
I give house at-transport you. (Maybe it's a mobile home and I'm physically conveying the object, rather than just statively conveying title)

My only "evidence" for this guess is that the French wikipedia claims that "pu" is used to avoid certain ambiguities, and the ambiguity of "pana e tomo tawa sona" was noted a long time ago.

Indeed, years ago. I'd be surprised if jan Sonja still has in mind what ever she had in mind several years ago for this particle.

Interesting idea non-the-less!

[janTe]

which makes me realize, why is 'noka' not on the new list of toki pona words?

I can see that there was a Yahoo poll to change "noka" to "jalan", but I don't know why. Can anyone enlighten me?

[janMato]

which makes me realize, why is 'noka' not on the new list of toki pona words?

I can see that there was a Yahoo poll to change "noka" to "jalan", but I don't know why. Can anyone enlighten me?

That was in 2002! Ancient history. What ever crime noka committed, it's got to be beyond the statute of limitations

[janTe]

You know what I just realised? In English, "poo" is an affectionate, diminutive suffix. For example, you can call your boyfriend "Mikey-poo". It's a little old-fashioned, though.

Could "pu" be a diminutive suffix? Esperanto has one, so jan Sonja would certainly be familiar with the concept.