Which of the following is true of bilinguals?
A. Bilingual speakers never mix the two languages in a conversation in any way.
B. A bilingual speaker is likely to mix the two languages in a conversation. This happens only because the speaker is not competent in one or both of the languages.
C. A bilingual speaker is likely to mix the two languages in a conversation. This happens even when the conversational partner speaks only one of the languages.
D. A bilingual speaker is likely to mix the two languages in a conversation as natural behavior for bilinguals conversing with other bilinguals.