@knell123 I would say so. The people who keep saying everyone speaks English here are wrong, possibly living in an Expat bubble, or maybe even trying to sell you something. We have traveled North to South in Portugal, Lisbon, Porto, Algarve, Silver Coast and in between. While a lot of people do understand some, or even a lot of English, a LOT do not, or do not feel comfortable enough to speak it. Even in the hospitals in and around Lisbon capital area, we have found that a good number of doctors and technologists do not speak English. A lot do, but your patient base likely will be a mix of older/younger, and a lot of older citizens may speak French but not English--at all, while a lot of younger citizens are only required to have one year of English language in public school. I will challenge anyone who tells you otherwise. Our son has been in and out of three hospitals for an emergency situation. In addition, basic services such as connecting utilities, asking a metro worker why the train access is closed, asking a bus driver if you are on the correct bus going in the right direction, discussing issues regarding your grocery store card, getting your haircut, getting an eye exam for glasses prescription, constantly translating web pages, etc. can turn into a headache, but it is on US the immigrants to learn, not the Portuguese to cater to us. After all, the immigrants are a big reason for the increase in their cost of housing.
I would also not rely on Duo Lingo solely to give you a good working knowledge of Portuguese, as it has a lot of phrases and words that may be totally useless in a functional, technical conversation. Anki is a good flashcard type program (open source and free) to use, and there are decks with the most common phraseology in European Portuguese, though there is a learning curve to using it. There are books available on Scribd (leave Amazon behind, PLEASE) that you can read and learn the techniques of learning all languages fluently and that are doable in a shorter time frame. You are going to have to immerse yourself in the language and read (grocery flyers, newspapers, etc.), watch Portuguese TV and news programs that have captioning in Portuguese to help you know what the subject is, listen to radio, and insist gently that the Portuguese do not tell you to "just speak English," because you really need to know Portuguese to be able to function comfortably. Listen to the accents, record your voice and play it back to get the subtle intonations. Portugal is an awesome country, filled with great people, but remember, WE are integrating into their society. Best of luck to you.