Some New Insight into the Historical Source of the Chinese Copula Shì/*deʔ 是 (關於繫詞'是'歷史來源的新思考)

The present study is mainly concerned with the nature of the demonstrative shì 是 as the historical source of the copula shì. Tracing the development of shì in bronze inscriptions from the 11th to 3rd centuries bce and comparing the patterns of change against two purportedly contemporary texts, Shī jīng 詩經 and Shàng shū 尚書, it argues that shì is not a typical demonstrative in origin because it only occurs pronominally and is strongly associated with the structural expression of focus in its early stage of development. On the basis of these observations, shì is analyzed as a special demonstrative that combines anaphoric and focalizing force to highlight and contrast a constituent that has been introduced into the discourse. It is then compared with the expressions wéi zhī 唯之and huì zhī 惠之 with the same function in the Shang oracle-bone inscriptions (13th–11th centuries bce). The investigation of whether shì is derived from wéi zhī only finds evidence indicating a morphological relationship with zhī, while the etymological link with wéi remains speculative. In conclusion, this study claims that the focalizing force of shì is important in answering the question why it is the only demonstrative evolving into a copula. The observed development of shì confirms that the origination of copulas is often related to the morphosyntactic expression of features of information structure. 本文擬對指示詞“是”的最初歷史來源進行探討。根據學界近年對指示詞的研究成果，本文提出“是”很可能在產生之初即具有促發其向繫詞轉變的特徵。通過對西周至春秋戰國金文資料中指示詞“是”的全部用例的研讀以及與《詩經》、《尚書》中用例的比照，本文發現“是”的早期用法均為復指，且僅出現在焦點位置，其產生與商代甲骨語言中獨有的“唯／惠之”的表達方式大有關聯，極大可能是“之”在焦點位置的形態變體。“是”以及“唯／惠之”在語篇中具有同樣的復指及聚焦的雙重功能，是焦點的句法表達手段，反映了繫詞產生與焦點的句法表達之間的密切聯繫。