According to the Introductory Discussion of Bilingualism

According to the introductory discussion of bilingualism,

A) more than half of the people in the world are at least partially bilingual.
B) technically, a multilingual is someone who speaks two different languages that have different historical origins.
C) a speaker's first language is the language that she or he currently speaks most fluently.
D) the majority of the world's bilinguals learned their second language during high school.