What is the difference between an expressive language disorder and dysgraphia?

They're related: In expressive aphasias, the individual knows what he/she wants to say but has difficulty communicating it to others. The form of communication can be spoken words or written words. Dysgraphia is an impairment in the ability to write and therefore can contribute to expressive aphasia. Further reading: http://www.ninds.nih.gov/disorders/dysgraphia/dysgraphia.htm

Yes: Expressive language problems are usually due to brain synthesis of intended output. Dysgraphia is more peripheral & refers to problems writing. One could have verbal expressive problems & no dysgraphia. Or dysgraphia & no expressive problems.