Ibn Caspi quote
Someone pointed out that Rabbi Dr. Twersky's article about Ibn Caspi didn't actually include citations on the topic of Dibra Torah. You can download Ibn Caspi's works at Hebrewbooks.org; his Mishna Kesef is here. Twersky has many references in the endnotes of his article, but here is one of the most important quotes, from page 49:
It's tricky to translate this into readable English. If someone has the time to do so, please post it in the comments.