Difference between Enough to make a cat laugh and Enough to make a cat speak

enough to make a cat laugh—said of smth. utterly ridiculous:

• The idea of a chap like that writing a book: it’s enough to make a cat laugh.

enough to make a cat speak—said of smth. very extraordinary or exceptional:

• I don’t know if this article is “enough to make a cat speak,” but you should read it.