In research as well as in educational and other settings the question of linguistic proficiency is critical. This question is something that I continually struggle with in working with children. How proficient is proficient enough? What does it mean? What should we measure? I’ve been influenced by my own clinical background and the work of other researchers in this area. Grosjean for example reminds us of the importance of the context or situation in which a person must communicate. And that those situations may vary by language. Li has developed a questionnaire for bilinguals to look at history of L1 and L2 learning, their experiences, and their self-reports of proficiency. Hernandez, among others focuses on the age at which a first and second language is acquired. But, how do you do all this with kids?
In research my colleagues and I use a combination of approaches. We look at history of L1 and L2 learning. We also look at current exposure to each language and amount of use in each language. Use and exposure are significantly, but not perfectly related. Sometimes kids hear proportionally less English for example than they use. Also, I think that what you measure in proficiency matters. Kids seem learn a lot of vocabulary before they can use it grammatically. So, if you measure proficiency via vocabulary you might get one answer to the proficiency question compared to if you use a measure of grammar.