The study of language attrition became a subfield of linguistics with a 1980 conference at the University of Pennsylvania called "Loss of Language Skills". The aim of the conference was to discuss areas of second language attrition and to discuss ideas for possible future research. The conference revealed that attrition is a wide topic, with numerous factors and taking many forms. Decades later, the field of first language attrition gained new momentum with two conferences held in Amsterdam in 2002 and 2005, as well as a series of graduate workshops and panels at international conferences, such as the International Symposium on Bilingualism (2007, 2009), the annual conferences of the European Second Language Association, and the AILA World Congress (2008). The outcomes of some of these meetings were later published in edited volumes.