Any board can be a keyboard in CoughDrop. Keyboards are just communication boards with an additional auto-suggest option enabled, and single-letter settings specified for each button. You can always use the default keyboard or define your own.
Create a new board
To make your own keyboard, first hit the profile icon in the top right corner and select "Create a New Board".
Specify the name and dimensions for your board, then hit "more options".
Enable word suggestion
Check the "Show word completion suggestions" box to enable word completion for your keyboard. Then hit "Create Board" to create it. Note that all of these settings are available after creation in the "Edit Details" section of the Edit Mode interface for the board.
Populate the board
Fill in the buttons you want to have on the board. By default, CoughDrop assumes that button labels contain whole sentences, not single letters. Single letters for spelling must be configured differently because of overlapping cases like "a" and "I". To set a button for spelling, hit the button and go to the "Sound" section in the button settings window.
Plus letter for spelling
In the "Speak" box enter "+" and then the letter or letters you'd like the button to spell out (for example, "+w" to add the letter "w" to the current word). Hit "Close" when you are finished.
Space bar for spelling
You'll also want to define at least one "space" key. When spelling more than one word, the user will hit a space key to end the previous word and start the new one.
Hit "Save" to complete the editing process and save your changes.
How spelling works in Speak Mode
Now when you load this board in Speak Mode you will be able to use the buttons to spell words. Spelling buttons cannot add to the end of existing words (see inflections for that), so the first spelling button you hit will always start a new word. Any buttons you hit after that will continue the word until you either hit a space button or select a non-spelling button.
While spelling the user will also see word completion suggestions. These are there to possibly save the user time by trying to guess what word they're starting to spell.