Most of my clients do not consider themselves bilingual even when they are fully functional in both their native language and in English. I try to challenge what their conception of bilingualism is. Most of them consider bilingualism a situation that arrives from childhood where they are raised to speak two languages. So according to them it is too late, they will never be bilingual....I totally disagree.
Looking for supporting evidence I found this under multilingualism Wikipedia
A multilingual person, in a broad definition, is one who can communicate in more than one language, be it actively (through speaking, writing, or signing) or passively (through listening, reading, or perceiving). More specifically, the terms bilingual and trilingual are used to describe comparable situations in which two or three languages are involved. A generic term for multilingual persons is polyglot. Poly (Greek: πολύς) means "many", glot (Greek: γλώττα) means "language".I also found a nice essay which I am only including the conclusion Bilingualism is an entirely subjective concept.. The point where a foreign language becomes a second language is "either arbitrary or impossible to determine" (Romaine, 1995). There is no norm or standard for language proficiency, which poses a problem for coming up with a psychological definition. Thus we lean towards a more sociological definition, which relates to the uses of two or more languages, rather than a measure of the speakers' aptitude in them (Appel and Muysken, 1987). This was reflected in the empirical data gathered.This was taken from
http://www.translationdirectory.com/article895.htmHow do we define a word that has no commonly understood meaning?
By Jodie Palmer
United Kingdom
This addresses my point that I make with my Students. They are bilingual! Yes they make some mistakes but we all do even when we only speak one language.