Ani Lopez provides good reasoning that we should offer distinct pages for translations, since we want to target those pages to a specific audience. Search queries will be most commonly in someone’s native language, we want to segment our analytics by target market. English should not be treated just as English, but as American English (en-us), British English (en-gb), etc. An Australian searching for “bangers” would be looking for a tasty breakfast meat. As an American that sounds like it might be NSFW. We need to recognize that supporting multiple languages in our web sites and applications is not just a checkmark feature, but an opportunity to address a new market.
SEO for international multilingual projects