Various linguists have examined words which are
traditionally called prepositions in Thai.
Warotamasikkhadit (1992) proposed that there are no
prepositions in Thai. Other linguists maintain that there
remain prepositions in Thai (cf. Savetamalya 1989;
Indrambarya 1995; Prasithrathsint 2000). Words which
appear in the following frame [NP V NP __ NP] have been
widely discussed and classified into various categories:
verbs (Indrambarya 1995), nouns (Savetamalya 1989;
Indrambarya 1995, Prasithrathsint 2000), prepositions
(Indrambarya 1995, Prasithrathsint 2000), adverbs
(Indrambarya 1995) or even conjunctions
(Warotamasikkhadit 1992)