Particles and postpositions in Korean

In Korean, certain postpositions which may be used on their own may be also combined with another postposition, while others are necessarily complex. This latter case is considered by some scholars as peripheral or secondary postpositions and weakly grammaticalized. I propose, then, to examine the hypothesis of the degree of grammaticalization based on particle-omissibility of complex postpositions, on the one hand, and the categorial status of particles, on the other.