This series of seminars will focus on First Language Attrition (FLA) - the process by which the first language of a speaker who uses another language predominantly (e.g. migrants) becomes compromised and shows signs of crosslinguistic interference, such as word-finding difficulties, a foreign accent, or lexical or grammatical errors. Personal accounts of such experiences abound and spark great interest online, e.g. a video recorded by a Canadian in Japan who describes 'forgetting her English' which had more than 70,000 views on YouTube (http://www.youtube.com/watch?v=QeBHl1PbhDQ).FLA is becoming an increasingly important subtopic in the wider research area of bilingual and multilingual development, and it is being recognised that investigations of changes in the first language of bilinguals have as much to contribute to our understanding of the human language ability as the study of second language acquisition (SLA). In addition, migrants often feel in need of good information regarding the process of first language attrition and how it may impact, for example, on their personal ties with their country of origin, their sense of identity, or the choices they make with respect to the language in which they bring up their children. For speakers who are professional language users (foreign language teachers, interpreters, tour guides etc.), the problem is particularly important, since an erosion of their first language proficiency may threaten their professional existence. It is also increasingly recognised that the differential use of all of a speaker's languages, in particular the potentially attrited native language, in treatments such as psychotherapy or speech/language pathology may facilitate recovery from conditions as diverse as depression and aphasia. That notwithstanding, studies on SLA still vastly outnumber those on FLA which remains a somewhat marginal topic of investigation. An international research network led by the PI in collaboration with some of the co-applicants and comprising a number of meetings, conferences, and panels at international conferences between 2002 and 2011 has helped raise the visibility of the field considerably. This seminar series will build on these efforts to expand the focus of attrition studies and explore overlaps and opportunities for collaboration and co-operation with neighbouring fields, in order to achieve greater insights into some fundamental questions about the human language faculty and, in particular, the nature of linguistic development across the lifespan. As in the previous meetings, there will be a focus on providing support and advice to PhD and early career researchers in particular through bringing them in contact with experienced researchers in the area and providing a platform for presenting and discussing their work and any problems or questions that they might have with the senior experts in the field.