Full Idea
In order to assert that p it is not necessary to utter exactly those words. ...Clearly, also, in order to assert that p, it is not sufficient to utter the words that were actually uttered.
Gist of Idea
To assert that p, it is neither necessary nor sufficient to utter some particular words
Source
Richard Cartwright (Propositions [1962], 07)
Book Reference
Cartwright,Richard: 'Philosophical Essays' [MIT 1987], p.38
A Reaction
I take the first point to be completely obvious (you can assert one thing with various wordings), and the second seems right after a little thought (the words could be vague, ambiguous, inaccurate, contextual)