Below are links to two short pieces, both online appendices to articles by Ian Mackenzie. The first is a statistical study: it samples a random page from a dictionary of English, and determines how easily the lexemes in question can be translated into Penan. As a control, the experiment is repeated with French as the target language. The second is a detailed semantic analysis of pelin, a Penan verb that is almost impossible to translate into English. Both downloads are pdf files.
Penan-English lexical comparison
(search terms "penan french lexicon" "pelin definition" "pdpelin")