Bi- or plurilingualism is the specific ability of a person to communicate in two or more languages, irrespective of their level of proficiency. Today we are not looking at equal proficiency or the sum of (two) monolinguals.
References:
"Bilingualism is the regular use of two or more languages or dialects in everyday life (...) many people who live with two or more languages do not have equivalent, or perfect, knowledge of them since they use their languages in different areas, with different people, for different purposes (...principle of complementarity)" (Grosjean, 2013).
Source:
Grosjean F. (2013), Interview given to the "A bonne école.net" website on Wednesday, 9 January 2013, Interview by Assmaâ Rakho-Mom, www.francoisgrosjean.ch/interviews_2013_fr.html/interviews_2013_fr.html accessed 27 July 2022.
"Bilinguals are not the sum of two complete or incomplete monolinguals; rather, they have a unique and specific linguistic configuration." (Grosjean, 1985, p. 467, own translation)
Original quote:
"the bilingual is not the sum of two complete or incomplete monolinguals; rather, he or she has a unique and specific linguistic configuration". (Grosjean, 1985, p. 467)
Source:
Grosjean F. (1985), "The bilingual as a competent but specific speaker-hearer", Journal of Multilingual and Multicultural Development, 6:6, pp. 467-477, DOI: 10.1080/01434632.1985.9994221.
"By bilinguals we mean people who use two or more languages (or dialects) in everyday life. This includes people who have oral proficiency in one language and written proficiency in another, people who speak two languages with different levels of proficiency in each (and who can neither read nor write either), but also, of course, people who have a very good command of two (or more) languages." (Grosjean, 2018, pp. 8-9, own translation)
Source:
Grosjean F., "Être bilingue aujourd'hui", Revue Française de linguistique appliquée, nº 232, 2018, pp. 7-14.
"A person's bilingualism is a dynamic process influenced by life events. The bilingual's linguistic configuration will evolve following major changes such as changes at school, entry into working life, the start of married life, moving house and/or migrating, the loss of a loved one with whom one of the languages was spoken, etc." (Grosjean, 2018, p. 9, own translation).
Source:
Grosjean F. (2018), "Être bilingue aujourd'hui", Revue française de linguistique appliquée, nº 232, 2018, pp. 7-14.