What is the use of the [Setting language] step ?

[romaincointepas]

1. The way I use youtube-dl requires the time between calling youtube-dl ... and getting the stream urls to be as short as possible.
   Here are the urls called during this step (sequential calls) :
   https://www.youtube.com/?hl=en&persist_hl=1&gl=US&persist_gl=1&opt_out_ackd=1
https://www.youtube.com/?hl=en&gl=US
2. Also, if only the itag and stream urls are being asked (in --simulate mode), could the /watch?v=xxx step also be avoided ?

[jaimeMF]

Actually you'll need the /watch?v=xxx if the video has encrypted signatures (we use the player configuration from that page).
The [Setting language] step is to make sure we always receive the English page and not a localized version, which may break some things (I'm not really sure about this). There's an open issue for avoiding it (#584). You get two calls because the first one redirects to the second url, but it also sets some cookies.
I think we can close the issue, do you agree?

[romaincointepas]

Thanks a lot for the explanation @jaimeMF, I've closed.