本論文依據現代客語語料庫，探討臺灣客語評注性情態副詞在語法化、詞彙化以及語用化運作之下的發展過程，以及情態與語言演變機制之間的關係。藉由三個知識性情態詞，本文對於評注性情態副詞之分佈、語義和句法特徵進行詳細的描述。藉由檢視其構式結構以及運用相關測試，證實評注性情態副詞不但遵守副詞修飾範域：話語行為副詞 > 情態副詞 (評論副詞 > 知識性情態副詞) > 附加副詞，也同樣依循情態詞之階層分佈：知識性情態詞 > 義務性情態詞 > 動力性情態詞。在他們所處之語意語境以及語用語境影響之下，語用推論的產生導引出重新分析，此轉喻強化現象，致使評注性情態副詞在階段發展中經歷了語法及語意之轉變。在語言使用之溝通目的下，評注性情態副詞透過語境誘發之重新解釋形成了歧義現象，並進一步固定化為獨立之語意。綜言之，奠基於臺灣客語語料庫之實際語料，本文提供了對評注性情態副詞全面的深入探索。研究結果具有兩項主要貢獻：將語法化，詞彙化和語用化的理論框架納入臺灣客語情態副詞之分析；並藉由語言實證展示情態與主觀性之間相互關係之理論模式。 / This dissertation takes a corpus-based approach in an attempt to explain the development of Taiwan Hakka modality disjuncts with epistemic interpretation on the theoretical ground of the mechanisms of linguistic change, including grammaticalization, lexicalization, and pragmaticalization. The main focus of this research is on the interaction between modality and the three mechanisms. A fine-grained analysis is provided to examine the morphological characteristics and syntactic structures of epistemic and evaluative modality disjuncts, exemplified by three cases in Taiwan Hakka. Several constructions and tests are manipulated to figure out the scope of modal disjuncts, which warrant the postulation of the scope hierarchy of illocutionary disjunct > modality disjunct (evaluative > epistemic) > adjunct, as well as the ranking of epistemic modal > deontic modal > dynamic modal. Thanks to their semantic-pragmatic contexts, the operation of pragmatic inferences lead them into reanalysis, giving rise to grammatical and semantic shift from one stage to the next. Metonymic strengthening is claimed to be the key to motivate such developments. The usage in a context triggers context-induced reinterpretation, resulting in ambiguity. Overall, this dissertation, probing into actual language usages from corpora, proposes a full-fledged analysis on modality disjuncts. The findings feature two significant contributions—an integration of the theoretical frameworks of grammaticalization, lexicalization and pragmaticalization into the analysis of Taiwan Hakka modality disjuncts; and a demonstration of linguistic investigation for the theorization on the relationship between modality and subjectivity.