本文從複雜系統的基本概念及應用，介紹與二語學習與發展的關係。 複雜系統研究 (Complex Systems Research) 是緣起於物理學的一門學術 領域。人類行為所展現的許多非線性型態與表現，適合以複雜系統的概念 與原則來探討。對於複雜系統狀態的變化， 主要以動力系統理論 (Dynamical Systems Theory, DST) 進行量化研究。人類語言的行為表現， 相當符合複雜系統特性，可參考一些現有以動力系統理論為基礎的運動行 為研究，作為全新的研究思維。母語是個人最自然的溝通工具，第二語言 是在母語基礎下所學習的另外一種語言系統。現階段以複雜系統理論作為 基礎的二語習得研究多以質性的方式進行研究，未來可嘗試以動力系統理 論的量化概念作為研究的架構，以供了解更多二語習得改變過程的具體因素。

Complex Systems Research is an area of study originating in physics. The complex systems framework is most appropriate for studying any human performance that exhibits many non-linear patterns of behavior, and the changes in the system state may be best analyzed under the guidelines of the Dynamical Systems Theory. Human language as part of the human behavior also exhibits many characteristics of complex adaptive systems. In this paper we provide examples of human motor behavior studies based on the Dynamical Systems Theory to demonstrate the availability of the research tool in investigating the human language development from the Complex Systems perspective. Exploring the processes of the second language development from the Complex Systems perspective takes into account all aspects of the language development. Although there has been some progress made in the research of the second language development based on the complex systems framework, and many observables have been proposed to qualitatively describe the developmental processes, the quantitative analyses of the changes in second language performance based on the Dynamical Systems Theory may provide additional information to further understand the dynamics that underpinning the second language development.