Hello, letter boards are great but we also made a picture board. We used a sheet of bristol board and cut out pictures e.g. toilet picture means I have to use toilet! Picture of a sweather means too hot or cold. Picture of a vacuum indicated the need to be suctioned. I 'm sure you get the idea.
Just cut out pictures that fit your situation.
The picture board saves tiring and time consuming spelling.
Hope this help
One idea may be to have a group of phrases you use often already in the form of a phrase such as : Thank You, I love you, Will you please__, Thanks anyways....etc.
Picture boards are great too, especially if you have the time/resources to print pictures of familiar things/people/activities.
You can also personalize them a bit by adding a border around the edge and using scrapbooking material ( on clearance at Hobby Lobby alot) Like if the person is a huge Nebraska Conrhuskers fan, or a fisherman, gardener,loves music, etc....pictures of loved ones.
Good luck and let us know how it turns out and any other ideas you come up with.