Writing is a complex task that requires skills & strategies at multiple levels. With teacher instruction, technology may assist at any of these levels.
To hone in on what exactly is difficult for a student, Dr. Denise DeCoste has developed the Writing Protocol. This assessment is available for circulation in the AT library (destiny.k12northstar.org). Contact Ernie Moore (Ext. 11377) to check it out. Learn more at: http://donjohnston.com/decoste-writing-protocol/#.VhwRW3gWpfc
Another excellent resource for analyzing specific difficulties with writing and matching assistive technology for the task is the WATI literature (Wisconsin Assistive Technology Initiative). See Chapter 5 in the WATI manual below.
Use Text-to-Speech (TTS) and Voice Recognition (VR) on a Mac computer for reading and writing tasks.