The article is devoted to a new format of speech interaction emerging between humans and generative language models. In contrast to traditional studies that consider artificial intelligence (AI) as a tool or a source of information, the authors propose viewing it as a new communicative partner whose involvement in speech activity changes the process of meaning-making itself. The paper substantiates the concept of “joint speech-thinking” as a dialogical process of sequential construction, clarification, and transformation of meaning. Based on an analysis of psycholinguistic mechanisms, the study demonstrates that interaction with a generative model is not limited to an exchange of prompts and responses, but becomes a form of distributed speech-thinking activity. Particular attention is paid to changes in the user’s speech behavior: in the course of such dialogue, the user is required to formulate thoughts more precisely and construct a more coherent logic of utterances. The article introduces the term “joint speech-thinking” into scholarly discourse and outlines prospects for psycholinguistic research on digital dialogue.