Your main problem throughout Catalunya is likely to be the language – Català (Catalan). Català has more or less taken over from Castilian, a phenomenon known as the venganza (revenge), though few visitors realize how ingrained and widespread the language is and sometimes commit the error of calling it a dialect. On paper, Català looks like a cross between French and Spanish and is generally easy to understand if you know those two but, spoken, it has a distinct, rounded sound and is far harder to come to grips with, especially away from Barcelona, where accents are stronger.
When Franco came to power, publishing houses, bookshops and libraries were raided and Català books destroyed. While this was followed by a let-up in the mid-1940s, the language was still banned from the radio, TV, daily press and, most importantly, schools, which is why many older people today cannot necessarily write Català (even if they speak it all the time). As for Castilian, in Barcelona virtually everyone can speak it, while in country areas, many people can sometimes only understand, not speak, it.
Català is spoken in Catalunya proper, part of Aragón, much of Valencia, the Balearic Islands, the Principality of Andorra and in parts of the French Pyrenees, albeit with variations of dialect (it is thus much more widely spoken than several better-known languages such as Danish, Finnish and Norwegian). It is a Romance language, stemming from Latin and, more directly, from medieval Provençal and lemosi, the literary French of Occitania. Spaniards in the rest of the country tend to belittle it by saying that to get a Català word you just cut a Castilian one in half. In fact, the grammar is much more complicated than Castilian, and the language has eight vowel sounds (including three diphthongs). In the text we’ve tried to keep to Català names (with Castilian in parentheses where necessary) – not least because street signs and turisme maps are in Català. Either way, you’re unlikely to get confused as the difference is usually only slight: ie Girona (Gerona) and Lleida (Lérida)..