Renward Brandstetter, An Introduction to Indonesian Linguistics…
“ In very many cases in IN languages there appears before a consonant a nasal, which is wanting in other IN languages, and which we cannot ascribe to Original IN either. The word for " brain " in some of the languages is utĕk, in others untĕk; "to pursue" is usir and uṅsir in Old Javanese. Now there are in the IN languages a great number of very commonly used prefixes and suffixes containing nasals, and it is from these that the nasal has forced its way into the interior of the WB by means of the principle of the repetition of sounds. ”
