Want to grasp Catalonia language in 18 mos

It's Catalan that you want. Besides, why do you think your basic Castilian will not serve you? Castilian is spoken and understood in the Catalan region of Spain. It's akin to worrying about learning Welsh prior to a trip to Wales. Whilst Welsh speaking residents will likely be impressed that you've bothered to learn the language they're not going to think any less of you for speaking English.

I would suggest focusing your efforts on improving your Spanish (Castilian).

If you are moving to Catalunya, you will indeed want to learn Catalan. If you are just visiting, you will be fine with Spanish (called Castillian or castellano in Spain). Outside of Barcelona, you will hear mostly Catalan spoken, but they will also be able to understand Castillian.

Thank you for your input. I will then focus on improving my Spanish. What is your suggestions for doing that? Taking Spanish all through highschool and college only got me to baby Spanish.

Chris,

I definitely agree with the others. Spanish is spoken in Catalonia by most people living there.

I will then focus on improving my Spanish. What is your suggestions for doing that?

I’ve had some success with the Pimsleur Language Program when reviewing French (also taken in high school years ago!) and learning beginning Italian prior to my trips.

You can check your local library and rent or borrow the language CD sets, and start listening to them daily.
Since you already learned the basics, it shouldn’t be difficult for you to review, relearn, and practice Spanish.

Enjoy!

@chrismastin.... this is always a controversial issue. These days in say, Brussels or in Berlin -to name two important cities- you can go by using English, as it has become sort of the modern lingua franca and lots of people speak it around the world (or at least mumble a bit of it). Yet if you ask a Brusselian or a Berliner, they'll most likely be kinder to anyone moving to their cities --that's different from just spending a few days!-- if they learn (or at least made the effort to learn) a bit of the local language, right? Same goes in Barcelona, while Spanish is "also" spoken -and it's indeed the primary language for a chunk of its residents- the local language is Catalan so, any native will be more appreciative if a foreign resident makes the effort, even if it's just the effort, to speak a bit of Catalan. I know I do! After all, it's another Romance language, so "similar" to French, Italian, Portuguese or Spanish, therefore not that difficult to learn.

Just a thought.

Resources: https://community.ricksteves.com/travel-forum/spain/spanish-language-school-in-near-barcelona

Check and see if your public library has access to Mango, an on-line program you can do from your home computer. There are also handy podcasts you can download (I used Coffee Break Spanish, a few years back). Or, if you find it difficult to stop procrastinating, look into taking a class at the local community college. Then you'll have assignments and quizzes you'll have to keep on top of.