“…12
M odal > conditional occurs in various languages, e.g. Dutch and English in (52).
Japanese and Korean use conditionals to express modal meanings (Akatsuka & Clancy 1993), some types of which have turned into modals, especially in the spoken languages, exemplifying conditional > modal .
The development of (53) can be represented as [ P - nai - to , ikenai ] ‘if not P , it is bad > [ P - nai - to ] ‘must P ’ (Fujii
2004), and that of (54), [ P -( a ) nakereba , naranai ] ‘if not P , it is not good’ > [ P -( a ) nakereba ( naranai )] ‘must P ’ (Narrog
2016). Both resemble fēi : ‘unless P (it is not possible)’ > ‘must P ’ and to a less extent, chúfēi : ‘(if you want P 1 ) only if P 2 (is P 1 possible)’ > ‘(if you want P 1 ) must P 2 ’.…”