 Prior work by our group shows that d-amphetamine and the dopamine precursor levodopa markedly improve word learning success in healthy subjects. In this randomized, placebo-controlled, double-blind trial, we probe whether daily administration of levodopa, coupled with a training of grammatical rules, improves the training success in healthy adults as compared to placebo administration. In the second step of this study, patients with dyslexia will be trained with the identical protocol. We postulate that the combination of intensive training in language rules and levodopa improves the reading, writing, and spelling abilities of patients with dyslexia. 