In Toki pona, words are never inflected, and many words can act as a noun, verb or adjective in different contexts. The word "li" usually separates the subject from a predicate, and “e” goes before the object (in SVO order). With soweli (animal), moku (eat, food) and kili (fruit), one can say:
soweli li moku e kili
The animal eats the fruit.
This is the usage listed in the dictionary section of the official book, Toki Pona: the Language of Good:
li. PARTICLE (between any subject except mi alone or sina alone and its verb; also to introduce a new verb for the same subject)
But there is another usage, as seen in phrase:
soweli li ijo
Animals are things (ijo means thing).
It seems that this usage increases the ambiguity, because
soweli li moku
can mean both ”The animal is eating” (with moku as an intransitive verb), or ”animals are food”.
What role does the li actually have in this phrase?