First, One for the recording of our own thoughts.
Secondly, The other for the communicating of our thoughts to others.
2. Any Words will serve for recording.
As to the first of these, FOR THE RECORDING OUR OWN THOUGHTS FOR THE HELP OF OUR OWN MEMORIES, whereby, as it were, we talk to ourselves, any words will serve the turn. For since sounds are voluntary and indifferent signs of any ideas, a man may use what words he pleases to signify his own ideas to himself: and there will be no imperfection in them, if he constantly use the same sign for the same idea: for then he cannot fail of having his meaning understood, wherein consists the right use and perfection of language.
3. Communication by Words either for civil or philosophical purposes.
Secondly, As to COMMUNICATION BY WORDS, that too has a double use.
I. Civil.
II. Philosophical. First, By, their CIVIL use, I mean such a communication of thoughts and ideas by words, as may serve for the upholding common conversation and commerce, about the ordinary affairs and conveniences of civil life, in the societies of men, one amongst another.
Secondly, By the PHILOSOPHICAL use of words, I mean such a use of them as may serve to convey the precise notions of things, and to express in general propositions certain and undoubted truths, which the mind may rest upon and be satisfied with in its search after true knowledge. These two uses are very distinct; and a great deal less exactness will serve in the one than in the other, as we shall see in what follows.
4. The imperfection of Words is the Doubtfulness or ambiguity of their Signification, which is caused by the sort of ideas they stand for.