Modern Greek has three complementizers (ότι, που and πως) along with a particle να which is not discussed here. The use and semantics of complementizers has been very much discussed since 1980s but the discussion is still not exhausted. This paper is based on the two approaches: fieldwork with different native speakers of Standard Modern Greek and Corpus-oriented research with Corpus of Modern Greek, the Greek Web Corpus and Hellenic National Corpus. Dialectal data from various Greek-speaking regions is also taken into account. As a result, it is possible to foresee how Modern Greek complementizers might change in future.