This conversation analytic study explores how a tutor and tutees collaboratively negotiate word knowledge in English as a second language (ESL) tutorials. Specifically, we focus on integrated vocabulary explanations, where explaining the meaning and use of a word is intertwined with teaching its spelling and pronunciation. The data come from 18 hours of dyadic and multi-party tutorials held at an urban community college in the USA. The findings show that for the participants such aspects of word knowledge as orthography, pronunciation, associations, connotations, syntax and grammatical functions form an essential part of vocabulary work. Notably, we argue that negotiations of these integrated vocabulary explanations are realized through multimodal resources, drawing on linguistic, prosodic, embodied and material resources, among others. The findings highlight the unique context of these ESL tutorials that affords individualization and immediacy, enabling tutors to be responsive to the tutees’ second language (L2) learning needs. The study also has implications for tutor education and classroom instruction with regard to the development of L2 word knowledge.