Fairly easy Metro system to use, even for foreigners. I mistakenly thought I needed to register…read morewith T-Mobilitat, but realized that is not needed so I cancelled that registration. Purchasing tickets are easy through the ticket machines. I purchased a T-Casual as that was more than enough for me. That amounted to about 12 EUR.
Note that because I arrived in Barcelona via the Renfe, I didn't need to worry about purchasing a separate airport ticket, which would've coughed up an extra 5 EUR.
Google Maps and the Citymapper app helped me plot my journey across my time in Barcelona, but the stations clearly point out the stops as needed. They do go a bit deeper underground, but the stations itself are more accessible friendly due to the 92 Olympics.
When inside the train, most of the announcements are indeed in Spanish, but you can figure out where you need to go. Just like most cities in Europe, remember to open the latch or press the button to exit the train.
Overall, an easy and pleasant way to get around Barcelona.