Immersion-breaking

i usually complain to the wife when horrible tactics are used in medieval battles.
like... why is everyone always doing a full frontal assault, have the wrong weapons, not use fire appropriately, never flank, use cavalry inappropriately.....
miltary tactics in movies is usually abhorrent.

Given the fact that any language used in such a movie is going to be wildly unlike the language spoken in the time and place of the movie, I think that's a mild anachronism
- Old English / Norman French etc would be practically incomprehensible to anybody.
  There was an interesting TV show called Barbarians a few years ago where all the Romans spoke Latin but with Italian accents but they had the Germanic barbarians speaking modern German. Not sure if that would please anybody.

Or that they're holding the bow drawn for a long period of time, waiting for the order to "fire".
Long bows averaged a 200lb draw weight. Try holding that for 5 minutes.

for the haters :
https://en.wikipedia.org/wiki/Volley_fire#Bows
The co-ordination and timing could probably be resolved with musical instruments, which were used to relay orders, messages etc.
EDIT : Also, what did OP expect, for all the characters to speak Old English?

Props to the movies that shout the "Loose!" command
- As I understand it, that's still not very historically accurate. It was not really a thing for archers to nock and loose together like they do in the movies.
  
  Never really made sense to me, loose all the arrows at once and then give a break between volleys? Gives everyone a chance to hide behind their shield, and then advance when it's clear. Unless volleys are perfectly timed between multiple rows of archers.
  Random arrows flying constantly never gives the enemy a chance to feel safe since it's a constant barrage, and there's no wasted time for the archers needing to wait for the command to fire.