Recording the home languages of schoolchildren has long been acknowledged as a useful way of mapping community multilingualism. However, the need to process large quantities of data on many different languages has meant that in order to assess the vitality of community languages, researchers have had to rely on schoolchildren's self-reported language preference and proficiency. Moreover, large scale data collection among minors poses ethical and data protection issues. We describe a pilot study carried out in Manchester, England, in which a method was tested to record home language proficiency based on rapid, anonymous speech acts. These were correlated with respondents' self-reported exposure to their home languages. The results indicate that different factors can play a role in language maintenance in different communities, and that home language maintenance does not have an adverse effect on proficiency in the majority language.