Сausal markers in Old Khmer

This paper considers causal markers in Old Khmer, the language of epigraphic 7th–15th century monuments found in Cambodia, Vietnam, Laos, and Thailand. Consistently looking at the contexts of two lexemes, hetu and man, it ascertains that hetu (traceable to the Sanskrit noun “cause”) was used in the 10th–11th centuries as a specialized conjunction to introduce causal clauses. Modern Khmer has transformed hetu into the conjunction haet tae. Modern Khmer also widely uses haet in various consequence phrases (as against its merely sporadic occurrences in this meaning in Old Khmer). The conjunction man is another ancient causal marker, probably ascending to Old Javanese. In consistence with modern views on the emergence of causal markers, its causal function may have developed from its earlier temporal uses (“when”). Man is not found in Modern Khmer, having fallen out of use as early as in the Middle Khmer, the language of the 15th–18th century monuments. Our probe into causal constructions with hetu and man could not come up with any examples of Old Khmer constructions with dependent nominal causal phrases, while these are common in Modern Khmer, though evidently — as derivatives of dependent causal clauses. The paper also looks into the potential emergence paths for the modern causal markers prʊəh and daoj(-saː). Our conclusion is that the registered occurrences of the Old Khmer ancestors of these words (roḥ and toy, respectively) provide no definite clue as to their evolution or the exact period when they or their derivatives assumed the causal function. Nevertheless, the existence of their modern Thai (pʰrɔ́ʔ, dûay) and Lao (pʰɔ̄ʔ, dûay ) counterparts suggests that the Old Khmer also used the respective causal markers that were later borrowed by Tai languages.