Doing some research on the number of people that might benefit from this project found this data:

Based on U.S. population studies, a little over 6,000 people in the U.S. are diagnosed with ALS each year. (That's 15 new cases a day.) It is estimated that as many as 20,000 Americans have the disease at any given time.

On this page:

http://www.alsa.org/about-als/facts-you-should-know.html?referrer=https://www.google.com/

It doesn't say how many of these people need communication augmentative devices such as we are attempting to make but I did find this company that makes low tech solutions (hence there name):

Also through the ALS page I found these people that make low tech solutions for commutations:

http://store.lowtechsolutions.org/

They list there products may be useful for people with:

• ALS (Amyotrophic Lateral Sclerosis)
  
• Cerebral Palsy
• Stroke
• Autism
• Throat/Mouth Cancer
• Temporary Communication Needs
  (for example, while intubated)
• Other Neurological Conditions