本文對臺灣四縣客語動後模態詞tet「得」進行描述和分析，首先探討「得」有別於典型模態句式呈現出的獨特動後語序；其次，就模態性（modality）而論，動後模態句展現了「模態光譜」（the spectrum of modality），下從辭彙層的能願模態、上至曲折層的義務模態。本文利用製圖理論（cartographic approach）探討其句法語義特質，並從比較語法的角度切入，以廣泛了解動後模態現象。動後模態結構一如典型模態句，模態詞組居於動詞組之上，表層的動後語序則是肇因於詞法要求，驅動動詞移位或者輕動詞架接，這兩類句法運作可從模態詞（modal）和副詞間的互動得到驗證。本文藉由客語動後模態詞研究配合跨語言比較，捕捉模態詞句法語義的對應關係，以及功能詞之間的互動現象。

This paper argue for a cartographic analysis (Cinque 1999, Rizzi 1997) of the unexpected postverbal position of the modal element tet in Sixian Hakka, an SVO language in which modal auxiliaries normally precede the main verb. I propose that the modal element tet patterns with regular modals in being syntactically higher than the VP, and crucially, that it behaves as an inflectional affix requiring a [+V] host. The surface form is derived to satisfy the morphological requirement of tet via either Move (V-raising) or Merge (with the light verb zo 'do'). The present analysis can explain the spectrum of modality (Tsai 2010) of tet, as well as the asymmetries in its scopal interaction with certain adverbials. Finally, in order to show cross-dialectal variation in postverbal modal construals, I compare Sixian Hakka tet with Hailu Hakka tet and Cantonese dak (Cheng and Sybesma 2004). This analysis provides a better understanding of the syntax-semantics correspondence in these modal constructions.