This isn't news worthy. It tells us nothing at the end of the day. Correlation ≠ causation. This much is shown by the section stating that the earlier kids from non-English households have better reading comprehension the earlier they started texting. Which is basically "sky is blue."

What this is, however, is a good starting point for further research. Why does this correlation exist? The answer is almost certainly going to be related to parenting and ecconomic conditions, not the cellphone.