No need for prep school for a language that has few prepositions. Pidanjinu, like Tok Pisin, only has two :
pu - n. possession; prep. of, from
sa - n. location, place; prep. in, at, on
These are also both used in metaphorical nominative compounds. Contrast the following:
fiwu-pu-wono ["grass belong mouth".] n. beard, mustache
hodan-fiwu ["rope grass".] n. munj, munja, Saccharum bengalense, Saccharum munja -- (tough Asiatic grass whose culms are used for ropes and baskets)
If the compound is a type of the modified noun (e.g., rope grass is a type of grass), then the adjective form of the modifier is fused to the noun: e.g., hodan-fiwu. If the compound is only metaphorically a type of the modified noun (e.g., a beard is not literally a type of grass), then the preposition pu is inserted between two noun forms: e.g., fiwu-pu-wono.