"vamos"/"vayamos"

Question

I know that "no vayamos" is the correct negative command for "ir"; but I was under the impression, and my Barron's verb book confirms, that the correct affirmative imperative for "ir" is "vamos" not "vayamos".

Answer

Hola Wylie
If we give an affirmative or negative command to "ourselves" as in "let's do something" or "let's not do something", we use (for both) the present subjunctive form. That applies to all verbs.
However, it is true that for the affirmative command using the verb "ir" we can use both: vamos and vayamos, the first coinciding with the present tense of ir for nosotros, the second coinciding with the present subjunctive of the verb ir for nosotros.
Using "vamos" is more colloquial and "vayamos" is more formal. If you are among friends it is likely to hear "vamos":
Vamos a la piscina. (Let's go to the swimming pool)
In a more formal setting, for example, with clients in the office, it is more likely to use "vayamos", for example:

Vayamos a la sala de reuniones, señores.
Let's go to the meeting room, Sirs.

I hope this clarifies it for you.
Un saludo
Inma

Answer

Hi Inma, is vamos as an imperative really considered colloquial? It seems odd that grammar books give this as the standard form. My grammar book suggests that vayamos is used as an imperative only in set phrases, e.g. vayamos al grano. Perhaps vayamos is now considered overly formal for normal use?

Answer

Thanks Inma. I appreciate your detailed, clear answer. It does clarify usage of the imperative for "ir".  It appears that Barron's Spanish Verbs is neglegent in not giving vayamos as another option for the 1st person plural affirmative command.

Answer

It's not just Barron's verb book, every other book seems to agree. I've also seen an explanation for this irregularity based on the fact that in old Spanish, vamos could also be a subjunctive. This is what the RAE says about it:

http://lema.rae.es/dpd/?key=ir

2. La forma vamos es hoy la primera persona del plural del presente de indicativo... pero en el español medieval y clásico era, alternando con vayamos, forma de primera persona del plural del presente de subjuntivo... Como resto de su antiguo valor de subjuntivo, la forma vamos se emplea, con más frecuencia que vayamos, con finalidad exhortativa... la forma de subjuntivo vayamos, con este sentido, ha quedado casi relegada a la lengua literaria...

Answer

Alan,

Yes, nowadays, the form "vayamos" is more formal and only used in more formal situations. This is why I gave Wylie two different examples, one using "vamos" to say let's do something among friends and another using "vayamos" to say let's do something in a formal setting (work related, e.g.with clients)

Saludos

Inma