If you are teaching students how to overcome or cope with speech disabilities, then it is reasonable to consider yourself as a "teacher" for purposes of deducting educator expenses. You would stillhave to meet the work-requirement test (900 hours, see below)
"If you are a teacher, instructor, counselor, aide, or principal that works at least 900 hours in a school that provides K–12 education, you can deduct up to $250 in unreimbursed expenses for books, supplies, and equipment used in the classroom."