Google is your friend.
From the French wikipedia (http://fr.wikipedia.org/wiki/Toki_pona
Le mot pu est une sorte de virgule utilisée pour éviter certains contresens.
In English: The word pu
is a sort of comma used to avoid certain misinterpretations.
I don't know who wrote that, and I don't know how they know that, but I notice that Sonja's mother language is French.
Hmmm. I wonder if pu
is intended to avoid confusion caused by words like tawa
which can be both modifiers and prepositions. Maybe pu
can be placed before the prepositional usages.
However, we also have http://en.tokipona.org/wiki/Talk:What_is_Toki_Pona%3F
, where pu
seems to mean "to have the official Toki Pona book". I can see why that would be a useful word for Sonja if she ends up doing a wildly successful book tour and long autograph sessions. (And it makes sense that the word hasn't been used yet, because the book doesn't yet exist.) As a noun, maybe the word will refer to the official Toki Pona book.
Oh man, wouldn't it be awesome if the book's title is simply "pu", and the word pu
isn't actually used or defined anywhere? It would be the first TP word to come into use through usage, rather than through definition.
I hope I haven't spoiled the surprise.
As for the word kipisi
, it apparently means "to cut", as stated in http://www.aboriginemundi.com/index.php/2009/12/toki-pona-five-new-words/
, and supported by http://en.tokipona.org/wiki/Talk:mun
. The author of the first piece wonders why we need the word kipisi
, when the word tu
already means "to cut", but I think the example of "mama kipisi" demonstrates why. "mama tu" would mean "two founders"!