情态动词“必须”的形成和发展

The Evolution of the Modal Auxiliary “bixu”

情态动词“必”与一般动词“须”连用在先秦便已出现。双音情态动词“必须”在唐代早期形成,有表动力情态中性必然性和道义情态必然性两种语义类型;至晚在南宋初年“必须”又出现第三种语义类型:表知识情态必然性。这一语义在清代消失。“须”在东汉演变成为与“必”同义的表必然性的情态动词,“必”“须”连用频率增加,为“必须”的凝固成词创造了条件。

The modal auxiliary “bi” and the verb “xu” co-occurred in the literature ever since the pre-Qin period. When the verb “xu” evolved into a modal auxiliary with the same meaning as “bi” in the Eastern-Han Dynasty, the frequency of the co-occurrence of “bi” and “xu” became much higher than before. This caused the lexicalization of “bixu” . While the disyllabic modal auxiliary “bixu” came into being in early Tang Dynasty, it had two kinds of modal meaning, i.e. dynamic modality necessity and deontic modality necessity. In early Southern-Song Dynasty “bixu” got the third modal meaning, namely, epistemic modality necessity. The last meaning of “bixu” vanished in the Qing Dynasty.