Bilingualism is the ability to communicate in more than one language and can be thought of as a continuum of language skills in which proficiency in any of the languages used may fluctuate over time and across social settings, conversational partners, and topics, among other variables (Grossjean, 1989; Bialystok, 2001). Bilingualism can be difficult to define due to the number of individual differences demonstrated by those who use more than one language. As a result, terms related to bilingualism often represent attempts to describe the process of language acquisition and include
- Simultaneous bilingualism—the acquisition of two languages at the same time, typically with both languages introduced prior to the age of 3
- Sequential bilingualism—a second language introduced after age 3, at which time some level of proficiency has been established in the primary language, also referred to as successive bilingualism or second language acquisition
- Dual language learners—individuals learning two languages simultaneously from infancy or who are learning a second language after the first language
- English language learners—"language minority students in the United States who are learning English, the majority language, for social integration and educational purposes ... also referred to as limited English proficient (LEP) students" (p. 265).
(Paradis, Genesee, & Crago, 2011)
Given the complexities involved in bilingualism and the significant variability that exists among the linguistic skills of multilingual individuals, clinicians must be prepared to address the unique situation of each client. Complex cases may lead to misdiagnosis, which in turn feeds into larger problems, such as disproportionality concerns in schools and health care disparities in hospitals and long-term care facilities.