In His Research on Bilingual Speakers, Lambert Found That

In his research on bilingual speakers, Lambert found that:

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