本文依据２５篇自然谈话语料，对西安市一家三代人使用河南话、陕西话、普通话的格局以及他们在家庭谈话中转换或不转换语码的原因、作用和意义进行了剖析。文章强调会话分析宜兼顾微观与宏观、形式与内容、静态与动态，并试图阐明选用同一种语言为何会产生多种社会意义、重复同一个语码为何其喻意功能不一。 Based on 25 corpus of natural conversation, this article analyzes the reasons, functions and meanings of using Henan dialect, Shaanxi dialect and Putonghua in three generations in Xi’an city as well as their conversion or non-transliteration of code in family conversation. The article emphasizes that conversation analysis should consider both micro and macro aspects, form and content, static and dynamic, and try to clarify why the selection of the same language produces multiple social meanings.