Hi 999!
First of all congratulations of having twins!
Don't worry!
This is probably a phase he is going through.
How long have you been using LittleReader? He probably has some more important activities he is engaged at the moment (such as learning more about his motor development, language, social relationships, eating,..).
I think this kind of phases are quite normal at least with my ten month old boy and they pass within a week or two. What we have done, we have skipped the LR for entire day and tried doing it only for a very short period (less than minute on the next day). Then we have added only short times more each days all the time noticing how the child is progressing.
I think it is very important not trying to push it but rather leave it immediately (before he looses focus) if your baby doesn't seem to be interested. I sometimes give an eatable toy for my baby, he eats while watching if he is having teeth. Also quite many parents have said in this forum that they never thought their baby was learning any of it because the baby was doing something else while watching LR. Then at some point these babies just started showing they had actually been listening and learning all the time!
Good luck! You know your baby the best and you are the best person to know what should be the next step. Hope this gave you any ideas what to do. Please share your progress with us!