Born and educated in the UK, with Arab parents and Muslims, second-generation British-Arab immigrants in Cardiff find themselves at the core of a complex web of power relations which potentiates their production of multilingual practices. However, while Cardiff is officially bilingual, English being the dominant language and Welsh becoming increasingly valuable, linguistic practices with Arabic are usually rendered illegitimate. In spite of this, British-Arabs produce, reproduce, and negotiate linguistic practices with Arabic in Cardiff. The present article employs Pierre Bourdieu's model of linguistic production and circulation to analyse the oral linguistic biographies of six second-generation British-Arabs in Cardiff in order to understand the conditions which enable the production of such practices in Cardiff in spite of their illegitimacy. The main argument is that Islam complements the central role occupied by the family in the reproduction of linguistic practices with Arabic in Cardiff; the relationship between the symbolic value ascribed to Qur'anic Arabic, the institutionalised provision of Arabic literacy, and mainstream education functions as a mechanism which reproduces the symbolic value of linguistic practices with Arabic on specific linguistic submarkets in Cardiff.