Re: I might be wrong, because I don't know
See my post above.
However, the printable characters are at a minimum 98 if you are using just the ASCII character set:
Which makes it 98*98 = 9,604 combinations.
However, there are, at a minimum 171,000 words in the English language. Therefore while yes, using 2 words from the dictionary is, in effect, using 'only' 2 characters, the size of the character set has expanded from 98 to 171,000, so 2 words would be
171000*171000 = 29,241,000,000 combinations.