Development of thùuk passive marker in Thai

Based on an approximately four-million-word corpus of Thai and some other related languages covering a time span of seven centuries (from the end of the 13th century to the present time), this study shows that the present passive marker in Thai (thùuk-) has developed from a lexical word originally meaning ‘to touch’ or ‘to hit on the point’. The development of this lexical word into the passive marker involves 8 stages: 1) lexical transitive verb thùuk ‘to touch, to hit on the point’ > 2) lexical intransitive verb thùuk ‘to be suitable’ > 3) lexical transitive verb thùuk ‘to suit’ > 4) modal intransitive verb thùuk ‘must, have to, to be obliged to’ > 5) modal intransitive verb thùuk ‘to be affected by’ > 6) modal intransitive verb thùuk – adversative passive marker > 7) auxiliary verb thùuk – non-adversative passive marker) > 8) the prefix thùuk-, the true passive marker in Thai.