I think the much better language would be the "no language" database. Throw portability to the wind and just have the client ship the query plan directly. The frontend to the database is howerver you want to expose it in your language of choice. I don't think there's any hope of getting disparate db vendors to agree on a compatible frontend language.
It seems easier to externalize it.
The closest existing database to this ideal is probably FoundationDB although it also externalizes the query planner, which I don't necessarily consider a downside.
There are some databases you need to write code to interface with. Somehow, one of the first things people need to add to them is a query language which is either SQL or something worse
I don't love SQL, but somehow the alternatives haven't beaten it yet
The closest existing database to this ideal is probably FoundationDB although it also externalizes the query planner, which I don't necessarily consider a downside.