Copulas Don't Have to Indicate Location

In the majority of languages, a copula subject is S. That is to say, it is marked the same way as the subject of an intransitive verb. It's not your stating a relationship, not an actual event. However, there are some languages such as I knew, for example, which does use the agent marking rather than the subject marking. So that T that I was making earlier, I make the T. The copula can be restricted to just identity definition, attribution, sometimes not even. Or you can have a particular copula for location that's different from your identity copula. And those usually historically are posture verbs.