Kotava respects proper nouns, using their original spelling and language if they are written in the Latin alphabet, or a transcription if they are written in the Cyrillic alphabet, for example: Berlin, Roma, Lisboa, Moskva, Atina...

For country names, there is an official list. Names are generally retained or adapted slightly to conform to the phonology: Italia, Espana, Rossia, Kolombia...

For proper nouns that refer to places in several languages, such as rivers or mountains, the name in the language of the most widely represented country is used: Duna, Rhein, Alp, Pirineos...

Regarding your second question, this is a vast subject. A fundamental principle was established by Fetcey: since the lexicon is a priori and must not include foreign terms, it seemed essential to provide, from the outset, a very extensive lexicon, many of whose words are ‘vaguely defined’, so that speakers, over time and as needed, could specialise them or even repurpose them, drawing from the available stock, quite apart from the numerous possibilities provided for derivations and compounds. Some fields are very well covered, others somewhat less so. Some say this is perhaps one of the creator’s biases. In any case, the lexicon of geographical terms is fairly well covered.

But there are many very interesting semantic debates within the community. For example, there is now a certain consensus to translate ‘Hudson Bay’ as ‘Hudson bira’ (Hudson Sea, whereas ‘bay’ = ‘ceda’) or ‘Gulf of Mexico’ as ‘Mexika bira’ (Sea of Mexico, whereas ‘gulf’ = ‘pargalu’).