In His Research on Bilingual Speakers, Lambert Found That

In his research on bilingual speakers, Lambert found that

A) bilingual speakers scored at least as well as monolinguals on performance tests
B) having to learn two vocabularies and two sets of grammar put bilingual speakers at a disadvantage on performance tests relative to monolinguals
C) people who learned a second language as adults showed superior cognitive processing compared to monolinguals matched on other variables
D) people cannot master the grammar of a second language if they begin to learn it after about age seven