tu vas au marché . will become Va au marché or Vas au marché

Question

Accepted Answer

To my knowledge, 'va t'en guerre' is used as an adjective or a noun, so no need to justify the -t  here as idiomatic.
You might say a bellicose person -
C'est un vrai 'va t'en guerre' = He's a real warmonger  
or of an government official -
Il est très va t'en guerre = He's very hawkish 
To go back to Sarita's question -
Normally the -s of the second person will be dropped in the imperative and this is also the case for 'aller'.
Va au marché me chercher du poisson = Go to the market to fetch me some fish 
But when a verb is followed by 'en' or 'y' a euphonic  -s or a -t-  is added in the imperative to make pronunciation possible .
If you try to say -
prend en , parle en ,  va y , pense y  you will see what I mean.
So you have to say , for the sake of euphony ( to create a pleasing sound) :
prends-en, parles-en, vas-y, penses-y ...
However, this is not always the case -
You can say -
Va y comprendre quelque chose! = Figure that one out!
Va en parler à ta mère = Go and speak about it to your mother
It is all to do with sound...
Not easy, but good question Sarita!

Answer

The imperative singular is irregular for this verb: va au marché! (there is no "s")

Answer

Oops, pressed "reply" prematurely.The question whether it is "vas" or "va" in the imperative of aller is, however, not clearcut. So, for easier pronunciation, it is vas-y (with "s"). Alas, it is va en vacances (without "s"), even though it would be easier to pronounce with the added "s". Sometimes, for ease of pronunciation, the letter "t" is added as in: va-t-en guerre!French speakers seem to differ in their use and there also seems to be a difference between written and spoken French.So, there you go. And you thought this was a simple question. :)

Answer

@ChrisI wonder if there is some confusion here with "va-t'en " = "go away" from s'en aller ?  This "t" is not for ease of pronunciation.Is "va-t-en guerre" really an imperative? It seems to be an adjective meaning "combative",  or a noun for a combative person, perhaps derived originally from a song?

Answer

Still more confused..

Answer

Hi Alan, the difference between va-t'en and va-t-en guerre is that the t in the former is the reflexive of tu, whereas in the latter it is just the phonetic "t" making it more easily pronouncable for French tongues. A "va-t-en-guerre" would be translated as "warmonger", so guerre is the substantive not the adjective.

Answer

Hi Chris, yes I understood the difference. My point is that I don't believe "va-t-en guerre" is an imperative, and I would be surprised if you could find any examples of the imperative with a phonetic "t", partly because of the possible confusion with "va-t'en".

The phrase "va-t-en-guerre" can also be used as an adjective.

https://fr.wiktionary.org/wiki/va-t-en-guerre

Answer

I know, Alan, this can be very confusing and I am not even sure all French native speakers would agree. Have a look at this discussion here:

https://forum.wordreference.com/threads/fr-va-vas-y-imp%C3%A9ratif.614126/

Answer

Thanks Cécile, could you just clarify a couple of things?

1. When "Va" is used as an imperative, is it ever followed by "t" for reasons of euphonia?

2. Do you ever say "Vas-en"?

Chris - I read that thread, I don't think there was any disagreement between the native French speakers there.

Answer

No, my personal "consultants" didn't agree on all points.

Answer

Hi Alan,
 I can confirm that you would know say - Vas-en.
You would say :
Va en chercher! = Go and fetch some!
Va-t-en! = Go away !
Hope this helps!