The linguistic and educational success of second language immersion education is now well established (see here). What has been less clear until recently was whether children who attend immersion programs show the same kind of advantages in cognitive skills, such as metalinguistic awareness and executive control, as do children who are early bilinguals. Metalinguistic awareness is our explicit knowledge of different aspects of language (sounds, words, syntax, and so on) and, when needed, our capacity to talk about these properties. It is crucial in the development of literacy, for example. As for executive control (also known as executive function), it is a set of complex cognitive processes that include attention, inhibition, monitoring, selection, planning, and so on. Inhibitory control, working memory, and cognitive flexibility are three core aspects of executive control.
In a recent study, York University professor Ellen Bialystok and her colleagues Kathleen F. Peets and Sylvain Moreno studied the development of metalinguistic awareness in children becoming bilingual in an immersion education program. They gave different tasks to second and fifth grade English-speaking children in a French immersion program and compared their results with those of children in a regular English program. The tasks involved morphological awareness (adding correct morphological forms to nonsense words), syntactic awareness (making grammaticality judgments), and verbal fluency (generating words that belong to a semantic category or that begin with an initial letter). These three tasks differed in their need for executive control, from the least in the first task to the most in the third task.