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.
The chief end of language in communication being to be understood, words serve not well for that end, neither in civil nor philosophical discourse, when any word does not excite in the hearer the same idea which it stands for in the mind of the speaker.

Now, since sounds have no natural connexion with our ideas, but have all their signification from the arbitrary imposition of men, the doubtfulness and uncertainty of their signification, which is the imperfection we here are speaking of, has its cause more in the ideas they stand for than in any incapacity there is in one sound more than in another to signify any idea: for in that regard they are all equally perfect.
That then which makes doubtfulness and uncertainty in the signification of some more than other words, is the difference of ideas they stand for.
5.

Natural Causes of their Imperfection, especially in those that stand for Mixed Modes, and for our ideas of Substances.
Words having naturally no signification, the idea which each stands for must be learned and retained, by those who would exchange thoughts, and hold intelligible discourse with others, in any language.