Professionals within the field of language learning have predicted that chatbots would provide new opportunities for the teaching and learning of language. Despite the assumed benefits of utilizing chatbots in language classrooms, such as providing interactional chances or helping to create an anxiety-free atmosphere, little is known about learners' actual use of chatbots during language classes or how chatbots affect their motivation to learn a language. To address these gaps, this exploratory study aimed to create an inventory of affordances that chatbots provide in the primary English as a foreign language (EFL) classroom and to explore how the affordances affect psychological aspects in language learners, particularly regarding their motivation to learn English through chatbots. Thirty-six Korean primary school learners participated in a 16-week EFL course that utilized customized chatbots. These chatbots were created using Google's Dialogflow. After the course, individual in-depth interviews were conducted regarding the participants' experiences and perceptions of the chatbots. Student-chatbot interaction logs produced during the course were also collected to supplement the interview data. Qualitative analysis of the interview transcripts and interaction logs revealed the presence of pedagogical, technological, and social affordances. Depending on the learner, the chatbot affordances were perceived differently; thus, each affordance acted as either an opportunity or a constraint for English language learning. In addition, this study specifically discussed how these chatbot affordances might have affected psychological states in language learners. Future recommendations regarding the use of chatbots in language classrooms were suggested from both pedagogical and technological perspectives.