Softetic just released an app dedicated to the smartphones and tablets: The BoxOfWords:

It can be used by people with aphasia to let the device speak sentences in their everyday life. Easily configurable, easily used!

You can find it in trial version for 15 days here: https://market.android.com/details?id=com.softetic.plp.bam.demo and in unlimited version without ads here: https://market.android.com/details?id=com.softetic.plp.bam

As usual, you get a discount for the first month of this new product!