This article takes a sociocultural linguistic approach to code switching in investigating discursive functions of shifts between Standard Japanese and a regional dialect (Iwate Dialect) in women's activity-centered, naturally occurring interactions. The paper extends previous scholarship to a consideration of how shifts are used for discursive functions such as expressing or seeking alignment; provides support for taking a talk-in-interaction theoretical perspective on code switching; and articulates a basis of support for this theoretical perspective by suggesting a methodological approach that combines close analysis of stretches of talk (DA/CA) with contextual information that informs our understanding of such talk (ethnography of communication). Furthermore, the paper illustrates the intersection of gender, region, and competing language ideologies; and contributes to the lacuna of language-in-use research on dialects in Japan. Excerpts are drawn from a data set of naturally-occurring interactions compiled over two years of fieldwork in Iwate Prefecture, Japan.