The language barrier is what you make it. My experience was that I travelled in South America some years ago without any Spanish beyond basic greetings, and it was difficult. When I decided to walk the Camino, I found a couple of beginner Spanish classes at the local adult education centre, and bought a learning Spanish CD and book, and played the CD to myself whenever I got the opportunity.
Once in Spain, I found this helped, but the language was far more complex, and spoken at a pace that was so rapid, that it often took some repeats to understand. At this point, mime and pointing are good fall backs, certainly not raising one's voice.
In South America, I carried a small notebook and pen, which I would offer to a vendor to write down the price of something. That wasn't as necessary on my Camino - most places had cash registers or the inevitable calculator that could be used to show one the price.
You will quickly learn some standby phrases. I think I could have survived on 'cafe con leche, por favour', 'gracias' and 'buen camino'. Don't forget the 'por favour' and 'gracias'. I am sure that I added them in some inappropriate places, but I feel its better to do that than appear impolite and ungrateful.
I found the locals in Spain always responded positively when I showed willingness to try. Some English speakers will put you out of your agony if they can, which helps. Everyone I met was helpful, even in the cities and big towns where I thought they might have been less tolerant of a non-Spanish speaking pilgrim.
I hope you have a similar experience.