No perfect way of doing this. There are several sources of words in the average person's vocabulary.
But most of us have a scrabble vocabulary that far outstrips the normal person's. Do you want to give up RETINAE or NEROLIS or QI or ZA, just because they are not in most folks vocabs or spellcheckers? Since Kwakle is not a commercial project, the developers are free not to listen to their customers, but there are enough out there asking for a lesser player mode.
