1. There is evidence that babies can communicate through sign language because of studies of hearing children of deaf parents, and recent studies have shown that children who were taught a form of invented baby sign language had higher IQ scores at age 8 than those who were not (Berke). However, it is recommended that parents who choose to teach their babies sign language use the approved American Sign Language which is used by the deaf to avoid confusion later on.
The periods of silence are not surprising. Learning language is difficult enough for a baby, and learning three languages at once is a tremendous load on the mental resources available. Distinguishing between which languages to use with whom adds another load. It is not said how old this child is, but obviously quite young. While babies do have the capacity for learning several languages, learning three at one time will slow them down.
2. There is no reason to teach sign language extensively through the school system because it will rarely be used and the burden involved in making every teacher proficient in sign language as well as in being able to teach it to their students is a major problem, not to mention adding another burden to the workload of students who would have to learn it too.
3. The signing being taught in this class is probably considered a novelty by the children at this stage. It would be too much of a burden to teach it throughout school and would be unused.
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