Full Idea
Rival systems of analytical hypotheses can fit the totality of speech behaviour to perfection, and can fit the totality of dispositions to speech behaviour as well, and still specify mutually incompatible translations of countless sentences.
Gist of Idea
Dispositions to speech behaviour, and actual speech, are never enough to fix any one translation
Source
Willard Quine (Word and Object [1960], §15)
Book Reference
Quine,Willard: 'Word and Object' [MIT 1969], p.72
A Reaction
This is Quine's final assertion of indeterminacy, having explored charity, bilingual speakers etc. It seems to me that he is a victim of his underlying anti-realism, which won't allow nature to dictate ways of cutting up the world.