How many unique words do you speak in a day?

(the root of this question is a different Fluther question that asked for lists of the thousand most common words)

Suppose that you had the patience to record and tally every word that you said in a given day. (what an awful task!)

How many unique words would you use in an average day?

For example – ‘the’ counts as one word, even if you say it 400 times.

Any ideas?

(Note that this is could very well be susceptible to the Hawthorne Effect)