If there is a problem with speech it is affecting an area in the brain called the frontal gyrus (Broca's area), that area controls speech in everyone. Its located in the frontal lobe of the brain. You both have young children so their brains are still making new neural connects and growing. Their brain will not be completely developed until they are 25 years old. With all the dropping it could be causing some brain damage, but I'm not sure if that will be perminate or not because of their ages. When someone has trouble speaking that is known as Broca's Aphasia.

Hi, my 3 year old sons speech seems worse after a seizure very slurred and also if he has a change in meds, it does seem to even out again as more time passes between the seizures. He's never been the greatest talker though. I wonder if speech is the more complex of tasks so it takes the hit of a seizure first? Sorry not much help but wanted to share my experience. Xx