This article examines the potential of pedagogical translanguaging in a community/heritage language context. With focus on Arabic as a multidialectal and multiglossic language, the paper primarily examines the function of translanguaging practices in teacher-learner and learner-learner interaction to construct and negotiate linguistic knowledge in the standard variety of the language. The results show that the learners' linguistic repertoires (multiple varieties of Arabic and English) are actively and dynamically employed in the exchanges to negotiate linguistic knowledge (lexical and grammatical) in a setting that venerates the standard variety as a medium of instruction with a monolingual policy. Also, the results show how these multidialectal practices are sometimes utilised to acknowledge and give voice to the heritage learners' dialectal identities. It is argued that community/heritage language learning contexts are ideal translanguaging spaces in which heritage language learners find ample opportunities for identity negotiation and knowledge construction. These opportunities are augmented in a classroom atmosphere that gives legitimacy to their dialects and challenges the monolingual ideology. Pedagogical implications are discussed for Arabic heritage and mainstream second language programmes with heritage learners.