Dragon Dictation is a very useful and FREE app. Several of my students use Dragon Naturally Speaking in the classroom setting to assist them in writing. Dragon Naturally Speaking (for a PC, etc) allows students to speak and the program is highly accurate at processing their speech and converting it into text. Dragon Dictation is a FREE download! As is Dragon Search. Within the therapy setting, I have used this app to allow a student to produce higher level, complex sentences that are converted to visible print. Depending on goals, the student is required to edit the sentences for grammar, articulation, or other errors. There is an information icon at the bottom right corner that provides tips for increased accuracy, or you can visit dragonmobileapps.com.
I'll try to post more therapy ideas as I use the app and iPad. I am sure there are many possibilities!
NOTE: You need wi-fi access to use Dragon Dictation.