I'm not sure that machine translation demonstrates compositionality, since it's translating from phrases already composed in one language to another. It only do

I'm not sure that machine translation demonstrates compositionality, since it's translating from phrases already composed in one language to another. It only does so if understanding composition is necessary for language translation. Whereas carrying on a meaningful conversation does require understanding of how words are being put together as the conversation evolves. Thus why the Turing Test hast been considered important for determining whether an AI has achieved human-level abilities, at least as far as language use is concerned.