語言變化是自然且不可避免的，了解字音變體使用者比例有助於我們了解音韻 系統演化成因和發展趨勢 (Au 2008)。近三十年來，關於臺灣華語語音的研究，議題廣泛、成果豐碩（蘇席瑤2018）。然而，在整個語言社群中各類型音變發生頻率與 相互關聯性如何？整體發展趨勢如何？民眾是否有所偏好？較少有文獻論及。何萬順 (2010) 亦指出現有語音研究多為零散片段的重點式分析，尚未有語言學家對其進行全面性描述。有別於語音聲學特質的描述或音韻規律的建立等研究傳統，本研究轉而探究變化中的語音變異現象，藉由大型語音語料庫證據，分析語音變異特徵和發展趨勢。研究發現：一、語音變異以聲調為主；二、讀音趨向簡化；三、字音創新可能填補空缺或擴充字音。

Language change occurs naturally and inevitably. Understanding the proportion of phonetic variant users is conducive to clarifying the causes and trends of the evolution of the phonological system (Au 2008). Over the past three decades, research on Taiwanese Mandarin phonetics has been broad in scope and rich in results (Su 2018). However, little research has been conducted in the Mandarin-speaking community of Taiwan on the frequency of phonetic variants, their interrelatedness, the trends of their development, and people’s preferences. According to Her (2010), most phonetic research has involved focused but fragmented analyses, and a comprehensive linguistic discourse remains lacking. Rather than a conventional analysis of an acoustic property or phonological rules, this study focuses on phonetic free variation. Empirical evidence was gathered from large speech corpora to analyze the characteristics and developmental trend of phonetic variants. The following results were obtained: (1) These variants are mainly characterized by tones; (2) pronunciation has been simplified; and (3) phonetic innovation may fill gaps in, or expand, the phonetic inventory.

多音字; 自由變異; 語言規範; 語料庫; 優勢變體

heterophone; free variation; linguistic prescriptivism; corpus; dominant variant