大牛椆方言是位於客語區內桃園縣新屋鄉下埔村及永興村的一個閩南語漳州腔方言島。居民經由廣東海豐縣移民台灣已經265年，雖然長期在客家語區的保護，仍然保有典型的原鄉方言特色，但複雜的語言接觸，使它吸收了很多潮州腔閩南語和海豐客家話的語言成分，因而形成一個口音特殊的閩南語。本文首先根據傳統方言學調查所得的資料，進行與漳州話、現代海陸豐方言、潮州話、客家話的比較，追尋大牛椆方言的形成，並追溯其漳州的發祥地。近年來大牛椆方言受到台灣優勢腔的影響，正在進行劇烈的變化，漸漸地喪失其原來的特色。本文的第二個目的就是根據社會方言學調 資料，考察這個方言受到台灣優勢腔的影響，而正在進行的變化。

The Tuaguitiau dialect of Southern Min is a small language island situated in the Hakka speaking area, Hsin-wu district in Taoyuan, Taiwan. The inhabitants migrated from Chang-chou of Fuchian via Lu-feng of Kwang-tung 265 years ago. Enveloped by the Hakkaese and Chao-chou dialects for a long time, the dialect borrowed some linguistic elements from Hakkaese and Chao-chou dialect, but it still maintains many essential dialectal features of Chang-chou. This paper focuses on tracing its homeland and its history, and analyzing its linguistic stratum diachronically, and its development synchronically, according to the data of traditional dialect survey and socio-dialectological investigation.