As for sitelen sitelen, "li" encloses adverbs and modal+verbs as well. "e" encompasses the DO and "pi" encompasses its phrase. That's useful for differentiating multiple pi-phrases from nested pi-phrases and separating a pi-phrase from other modifiers after it e.g. jan (pi pali pona mute) and jan (pi pali pona) mute. 'la' seems to be treated like punctuation marks in Josan's site lessons, but behaves similarly to "pi" in his famous contract with Mato. In my opinion, it's better to use it encompassing it's argument, because again we can distinguish nested 'la''s from multiple 'la'''s. "o" encompasses the vocative or the subject in sentences like "jan lili o musi." be it optative or vocative+imperative I suppose, because for Josan only the latter was possible (but if it's only vocative, then it's followed by a comma glyph). The vocative seems to come after "o", as consequence, but it's actually inside "o" and the reading doesn't change. Josan's Lessons don't make some rules clear, in some cases we have to search for examples. Aside from that, I'm particularly not sure about how to handle prep-modifiers, because they require "pi", but Josan simply sticks prepositions after the noun it modifies, and it is clear they are prepositions because prepositions encompass their objects, thus "pi" becomes redundant. Also the ordinal numbers were handled with "pi" at the time he created sitelen sitelen, but maybe now we can just put blocks together in sequence just like normal writing. In addition to that, it's always possible to write any word, including prepositions and particles, using the syllabary, and in that case the encompassing rules don't apply, although I'm not sure if words with more than one syllable can be written as such (couldn't find any examples), but I suppose they can, from what he says when teaching the syllabary.