Its been a while now since i have shout "Become ethereal" , problem is, i still cant use it because i need, as it says there, dragon soul, and thing is, since i got it i already killed 2 dragons, and still i didnt unlock it, its still gray and i cant equip it to use it.

What em i doing wrong?

Did you activate it? Like by pressing X

Have you pressed X or whatever button for the platform you're on it is to unlock it?

I have the same problem. I'm thinking all you need to do is slay more dragons and then once you have enough unlock the shout. But I could be VERY wrong.

Highlight the shout you want to learn and if you do have dragon souls there will be an "Unlock" option. I think the default is R for PC.

You press R to unlock new words in the shout menu.

Press 'R" on PC to spend a soul to unlock the shout (has to be repeated with each upgrade of the shout)

Don't you need to the greybeards to be able to after the first one?

Where'd you find the word wall for this shout, I'm dying to get it

keep doing the MQ you'll get it