In Tagalog, there is a particle called a linker or a ligature, with two forms: na and -ng /-ŋ/. The ligature's main function is to link modifiers (like adjectives and adverbs) and the words that they are modifying.
This ligature is found in other languages in the Austronesian language family. My question is, what other languages outside of Austronesian have such a particle with a similar function? I am mainly interested in how widespread it is, and if there are any theories as to its diachronic origin in these other languages.
The Bantu language Kinande has a somewhat peculiar condition that two object NPs in the VP must be separated by what is traditionally called an "associative" morpheme, which was terms a "linker" by Mutaka in an unpublished 1985 paper. This is where the term comes from, as far as I know.
This is discussed in a number of subsequent papers by Baker & Collins (2006), Schneider-Zioga (various); and also documented in Baker & Collins for Ju /'hoasi. The function of that kind of linker is similar to but not the same as the NP-internal usage found in Iranian (Izafe markers). I think it depends on what the properties of Austronesian "linkers" are that are of interest to you.
Japanese has a class of adjectives often called in English "-na adjectives". When used attributively, these take the particle na between the adjective and the following modified noun.
静かな人 shizuka na hito
quiet [ATTRIBUTIVE PARTICLE] person
Despite the surface similarity to Tagalog's na ligature, the Japanese particle arose from a contraction or fusion of construction ni aru (obsolete, now only found in historical writings) → naru (archaic, still used in poetic or formal writing) → na. In the original ni aru form, ni is an adverbial particle, and aru is the attributive form of the ancient copular verb ari.