Is there some kind of "precedence" when using multiple persons with a single verb?

Question

Let's say we have this:

Yo sé.
Tú sabes.
Él sabe.
Nosotros sabemos.
Vosotros sabéis.
Ellos saben.

So far so good. However:

Tú y yo sabemos. --> Person: Nosotros?
Tú y él sabéis. --> Person: Vosotros?
Nosotros y ellos sabemos. --> Person: Nosotros, why not ellos?
Tú y todo el mundo sabéis. --> Person: Vosotros, why not ellos o nosotros?

It looks like there is an established order between persons, is it so?
How do we know which one to use when there's many different persons?
E.g. Ellos, yo y tú mismo {sabemos? sabeis? sabes?}.

Answer 1

Castellano

Sí, hay una prioridad con las personas a la hora de concordar el verbo, lo he descubierto investigando para mi pregunta sobre sujetos compuestos. La primera persona tiene prioridad sobre las demás y la segunda la tiene sobre la tercera.

En Wikilengua leemos:

Si los sujetos son de distinta persona, el verbo concuerda en plural con la persona que tenga prioridad (la primera persona tiene prioridad sobre la segunda y tercera; y la segunda, sobre la tercera).

Juan y yo iremos al cine, así que tú y Olga tendréis que esperar un rato hasta que lleguemos.

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English

Yes, there is a priority with people when it comes to agreeing with the verb. I found out while investigating for my question about compound subjects. The first person has the priority over the other, as well as the second over the third.

Answer 2

It all depends on what you want to emphasise.

Tu y yo sabemos = Nostros sabemos.

The thing is that when you say "nosotros" it could be an unlimited number of people. Let's put an example:

• Me and you know he is cheating on her .- Here the emphasis is that you and me know something. I am not talking about other people
• We know he is cheating on her. .- Me and you know it but there could be other that know it too.

There is not and established order between people. However, as @blonfu points in the comments, the use "yo" the last is a respect formality, not gramatical rule.

Therefore, normally the rule is to put "I" (YO) is the last.

Example:

You could never say "Yo y tu sabemos", the proper way to say it is "Tu y yo"; "Yo y ellos pensamos..." the proper way is "Ellos y yo pensamos...".

If you can't say " Ellos, yo y tu sabemos.." the right way is:

"Ellos, tu y yo sabemos".