臺灣客語以四縣、海陸、大埔、饒平、詔安、南四縣6大腔調為主流，然在現實語言實踐中，由四縣腔與海陸腔自然融合而成的四海腔，已成為語言接觸地區民眾習以為常的母語。在現行強調標準化的語言政策下，四海腔往往被視為非標準之變體，處於政策邊緣。本研究旨在探討四海腔在國家語言標準化推力下的生存處境，並檢視政策能如何因應地區性腔調變體的多樣性。 本研究核心提問包含四海腔使用者的語言生命經驗為何？現行政策對其產生何種影響？以及政策應如何調整以兼顧標準化與在地多樣性？研究採用半結構式訪談法，於楊梅與吉安兩地共訪問44位參與者，涵蓋一般民眾、客語教師、傳播媒體從業人員、政府單位人士及學術研究者，藉此蒐集多面向的訪談資料。 研究發現，四海腔具備高度的溝通效能與在地認同，但使用者進入講求標準化的公領域後，常因被糾正而產生語言不安全感，尤以50歲以下研究參與者更為顯著。此外，現行客語政策雖嘗試透過教材標註等方式納入變體，但在行政執行與認證制度上，仍難以緩解四海腔使用者的邊緣感。本研究建議，語言政策應從單一標準化轉向多元共存的思維。參考國外地方變體之處理案例，政府應在客語認證、教材編寫及傳播媒體中，給予地區性混合腔調更多法規肯認與呈現空間。唯有包容語言的自然演變，方能真正落實語言平權並促進客語的長久傳承。;Mainstream Taiwanese Hakka is primarily categorized into six major dialects: Sixian（四縣）， Hailu（海陸）， Dapu（大埔）， Raoping（饒平）， Zhaoan（詔安）， and Southern Sixian（南四縣）. However， in actual linguistic practice， the “Sihai”（四海） dialect—a natural fusion of Sixian and Hailu—has become the daily mother tongue for residents in language contact area. Under current language policies that emphasize standardization， the Sihai dialect is often regarded as a non-standard variant and relegated to the periphery of policy-making. This study aims to explore the survival of the Sihai dialect under the push for national language standardization and examines how policy can respond to the diversity of regional dialectal variants. The core research questions of this study include: What are the linguistic life experiences of Sihai dialect speakers? What impact does current policy have on them? And how should policy be adjusted to balance standardization with local diversity? Adopting a semi-structured interview method， this study interviewed 44 participants in Yangmei（桃園楊梅）and Jian（花蓮吉安）， including general citizens， Hakka language teachers， media professionals， government officials， and academic researchers， to collect multi-dimensional interview data. The findings reveal that the Sihai dialect possesses high communicative efficiency and strong local identity. However， when users enter the public sphere where standardization is prioritized， they frequently experience linguistic insecurity due to being corrected—a phenomenon particularly significant among participants under the age of 50. Furthermore， while current Hakka policies attempt to incorporate variants through methods such as textbook annotations， the sense of marginalization among Sihai speakers remains difficult to alleviate within administrative execution and the language certification system. This study suggests that language policy should shift from a mindset of “single standardization” to one of “pluralistic coexistence.” Drawing on international cases regarding the treatment of regional variants， the government should grant regional mixed dialects more regulatory recognition and representational space in Hakka certification， textbook compilation， and mass media. Only by embracing the natural evolution of language can true linguistic equality be realized and the long-term heritage of the Hakka language be sustained.
