English-- "[That we are linguists] is good."
Subordination refers to hierarchical structure-- as the subject of that sentence, "that we are linguists" is still subordinated/embedded. It doesn't matter whether it comes at the beginning, at the end, or in the middle.
Again, this is definitional. Something that is not subordinated might be, for example, coordinated:
"John sang a song and Mary rode a bike."
In that case, the two clauses are independent. But obviously neither is an adverbial clause.