Say What You Will by Cammie McGovern

Born with cerebral palsy, Amy can't walk without a walker, talk without a voice box, or even fully control  her facial expressions. Plagued by obsessive-compulsive disorder, Matthew is consumed with repeated thoughts, neurotic rituals, and crippling fear. Both in desperate need of someone to help them reach out to the world, Amy and Matthew are more 
alike than either ever realized.