In my Spanish class I have learnt that only the second person (s & pl) has distinct forms for the imperative, but the forms for all other persons are the same as for the subjunctive.
Pragmatically, that's all I need to know to express myself, but from a linguistic point of view, I'm interested to find out if the fact is that there is no imperative for other persons, but that we use a subjunctive expressing a desire or demand (I know that this is the case in Latin, in which the sole exception is a future 3rd person imperative).
So when I say "no hables", am I using an imperative (that just happens to look like a subjunctive) or a (jussive) subjunctive?