These articles do not convince me at all because:
1) they equated "language" with spoken/verbal language development (which is a clear evidence of research bias right out of the gate)
2) only one measure of reading was used (we all know that they actually probably administered 3-5 reading tests and they chose the one that happened to showed a significant relationship) and Figure 1 results of the reading test with the error bars are actually unimpressive to me - they achieved a p=0.02 on this one single measure of reading probably because they controlled for so many other factors;
3) they did not control for post-CI rehabilitation ("over 95% of the children received specialized intervention during some or all of the first 3 years postimplant") - it is very likely that those parents who chose to sign more are those who did receive very much post-implant services, which is important because post-implantation rehabilitation is an educational experience. Anybody who gets additional educational experience is likely to show some benefits from the services, independent of whether or not their CI actually benefits them.
4) "The selected sample had statistically significantly younger age at implant activation (21.8 vs 37.3 months) and a higher percentage of families with white race (70% vs 55%) and with maternal education level at college graduate or higher (57% vs 42%) compared with those 91 families in the database who were not included in these analyses." - that is 91 families out of 188 children in the database (about 50%) so really, this is very likely just a study of the top 50% CI achievers. These important discrepant demographic variables between families who were selected in this study and families who were not selected and cannot be ignored without at least one study that actually includes the bottom 50% CI achievers.  Especially without case-matching, this is a clear evidence of subtle SELECTION BIAS since we all know that white people with higher education levels will have children who read better.