Hello Maciamo,

probably I don't know much more about Bahasa Indonesia than you (and maybe I should better ask my Indonesian friends) but I think that doubling is not a plural in a grammtical sense but gives "enhanced" meaning to words. Word e.g. is kata but kata-kata is not just words but a sentence, orang is person but orang-orang may refer to a tribe or nation (actually orang alone already means people and I experienced Indonesians to use "people" for a single person), jalan is the street and jalan-jalan might be journey (using many roads probably) or means to take a walk (maybe also detour but I cannot remember). At least that is how I understood it.

Regard the similarity of suka and suki.: This also struck me in one of my first Japanses lessons but I think that could be pure coincidence. There was a very intersting issue of the German publication "Spektrum der Wissenschaften" dealing with the development and history of human languages. The basis of linguistic sciences is, simply put, comparison and one article warned against "obvious" analogies.

Finally you may find many Sanskrit words spread by Buddhism in Indonesian and hence may found similar words in all of south and sout-eastern Asia.

Just once again, I'm not a linguist and all I had to say might have been wrong but this topic has always excited me and your contribution is extremely interesting.