If proper grammar and spelling is an essential function of the job, and one would assume that it is given that you are responding to emails, then you were unable to perform the essential functions of the job. So I doubt seriously that you will win this one.
If a team leader was keeping you informed regarding meetings, etc., including what was going on in those meetings, then you essentially were provided accommodations.
The ADA states that if a qualified individual can perform the essential functions of a job, either with or without accommodations, it is illegal to discriminate in employment. You were not able to perform the essential functions.
