This study reports on the role of parents in intergenerational language transmission in a Chinese city. Thirteen families’ everyday communication practices have been collected, including dinner table talks, homework tutoring, and children’s playtime interactions. Through comparative conversation analysis, the study uncovers the phenomenon of ‘medium translation’, a de facto language practice in three-generation households that use Fangyans (also known as Chinese dialects) and Putonghua (also known as Mandarin or standard Chinese) in their daily communication. The analysis of data revealed that grandparents played a key role in childrearing and children were exposed to Fangyan from birth in the families. Meanwhile, parents also played an important role as ‘medium translators’ in intergenerational transmission and contributed to the loss of Fangyan when it was passed down from the grandparents’ generation to the children’s generation. Language shift was, thus, ‘translated into being’ as parents mediated children’s language shift from Fangyan to Putonghua. The study has important implications for the maintenance of linguistic varieties such as Fangyan in China and other similar contexts.