D7+ i18n: What is the normal way: a single node with 2 translations or a different node for each translation
I believe this is the normal way. In /admin/content it lists the content and you can sort by language.

It knows which belong to which because it writes that info into the node table in the database by defining the 'tnid': The translation set id for this node, which equals the node id of the source post in each set.