I have previously attempted to find word squares with words as diagonals for squares of order 9, 8, and 7. As the order of the square decreases, it becomes possible to use more familiar words. The six rows and three diagonals of six-squares make nine words: in all the examples in this article, the majority of the nine words are in the most-used 87,000 words (British National Corpus): in the square, just two words do not appear in the top 87,000.
"All-Diagonal Six-Squares With Familiar Words,"
Word Ways: Vol. 39
, Article 10.
Available at: http://digitalcommons.butler.edu/wordways/vol39/iss3/10