Learn aggressively, not passively
"This is going to be much easier than I thought." That was what first crossed my mind as I sat smugly through my opening intensive Portuguese class after making the move to Lisbon. I understood every word the teacher was saying and surprised myself with how much vocabulary I already had my disposal.
I spent four weeks in a private language school, flying through various levels of the ludicrously named "Common European Framework of Reference for Languages" and started to wonder why I couldn't revise my tentative timeframe on eventually adding Portuguese.
I could read much of what I came across in the newspaper (we'll just gloss over the fact I only read football daily A Bola) and my knowledge of French and Italian allowed me to join up the dots when an occasional word escaped me. The adding process was running like clockwork. After all, you only need a passive understanding to secure another C language, right?
Passive comprehension and active communication skills in a language are not mutually exclusive. You can't simply uncheck the box marked "speaking" and replace it with a second chapter of your book or a third podcast of the day. So much of the French and Italian I learned was during informal situations with a variety of speakers. Angry, drunk, elated, facetious, hyper-active, sarcastic and shy. I've experienced the full spectrum of moods. I've ran into mumblers, gesticulators, introverts, extroverts, spitters and shouters.
Depending on which study you read, as little as 7% of communication is verbal. How can you do the haughty speaker justice if you can't even understand when he's being haughty and why? You have to get out there and witness these social situations firsthand. You need to pick up on what someone says and how they say it. It's much easier to establish when someone is being pompous in a language if you've already been on the receiving end of similar behaviour in the past.
In theory, plenty of "passive" content should suffice to add a C language. Immerse yourself in television news broadcasts and political debates on the radio. Read the paper cover to cover. Pore over lists of quirky idioms.
In reality, that simply doesn't cut the mustard.
I am a big believer in living your life as much as possible in the language you're looking to add. Speak it first thing in the morning and last thing at night. Learn to adjust your register while ticking off your to-do list. Seize priceless tidbits of vocabulary while performing everyday errands. Work out how to plead effectively for your landlord to bail you out while you're up to your ankles in filthy water.
Nothing will properly prepare you for that mission auditing the serial number on that tractor in the Azores. But at least give yourself the best possible chance of success. Yes, you can do a great deal remotely and, in hindsight, I'd have been better off in the long run had I moved to Lisbon with a better grasp of Portuguese. However, do not underestimate the importance of the small exchanges - the taxi driver ranting at you in rapid-fire slang, for instance. They are impossible to replicate sat in a classroom or at home studying.
Learn as much as you can before moving abroad and then savour every moment of your spell overseas. Do not approach the adding process with a C in mind. Why limit yourself? Discover the language in all its glory and, who knows, one day it might even be listed as a B language on your CV.