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. Also,
simultaneous bilinguals may not have a language that is indistinguishable from that of a native speaker or a language where their knowledge of it is less extensive than a native speaker's; therefore testing for attrition is difficult.
Types of attrition L1 attrition L1 attrition is the partial or complete loss of one's first, often native, language. This can often result from immigration to an L2-dominant region, daily activities in L2-dominant environments, or motivational factors.
L2 attrition L2 attrition is the loss of one's second language, which can result from cross-interference from L1 or even from an additional third learned language ("L3"). Unlike L1 learning and attrition, L2 learning and attrition is not a linear phenomenon and can begin in multiple ways: vocabulary loss, weakened syntax, simpler phonetic rules, etc. In Hansen and Reetz-Kurashige (1999), Hansen cites her own research on L2-Hindi and Urdu attrition in young children. As young pre-school children in India and Pakistan, the subjects of her study were often judged to be native speakers of Hindi or Urdu; their mother was far less proficient. On return visits to their home country, the United States, both children appeared to lose all their L2 while the mother noticed no decline in her own L2 abilities. Twenty years later, those same young children as adults comprehend not a word from recordings of their own animated conversations in Hindi-Urdu; the mother still understands much of them. Yamamoto (2001) found a link between age and bilinguality. In fact, a number of factors are at play in bilingual families. In her study, bicultural families that maintained only one language, the minority language, in the household, were able to raise bilingual, bicultural children without fail. Families that adopted the one parent – one language policy were able to raise bilingual children at first but when the children joined the dominant language school system, there was a 50% chance that children would lose their minority language abilities. In families that had more than one child, the older child was most likely to retain two languages, if it was at all possible. Younger siblings in families with more than two other brothers and sisters had little chance of maintaining or ever becoming bilingual. ==Manifestations==