You shouldn´t have any problems finding other backpackers and travelers in Barcelona. It´s easy to meet your new hangout buddies at the hostels that you stay in.
In Barcelona, the Spanish that they speak is Catalan and is different than the Spanish that you´re used to Castellana (Mexico, Argentina, Cuba, etc...). Either way, if you´re good at charades, you should be able to get around okay.
Some popular hostels in Barcelona are Kabul hostel, Gat Raval hostel, Pension Bahia, and Ideal Youth hostal. Some can be found on this link Barcelona Hostels
. These hostels are pretty popular so some of your nights should be booked in advanced, if you want to avoid any hassles.
Have a great time!