What’s the best way to learn if I already speak another Romance language?

If you are a native or proficient speaker of another Romance language, your journey will look very different. An initial easy win will be getting used to the way the language sounds. Romance languages have many cognates, but at the beginning they will be hard to recognize. Once you get some familiarity with the pronunciation and with the patterns in which words change from one language to the other, your comprehension will skyrocket in a very short amount of time. Just by watching just a handful of hours of intermediate or advanced videos about topics that you are familiar with or that interest you, you will get used to the pronunciation enough and will have learned some of the most common connector words, and that will help you increase your comprehension a lot in a very short time. This phase may be slightly longer if instead of Spanish or Italian you are learning Portuguese, or especially French. After this, you may find that some native media is already accessible. We recommend you start watching or listening to things about topics that you are already familiar with. Presentational content like podcasts, TED talks, or nonfiction audiobooks will be some of the easiest things for you to understand. Once you can understand native media well, we recommend you continue watching our advanced videos only if you are genuinely interested in the topic that we are discussing and if you find them more engaging than the native content that you can understand well. Pretty soon you’ll get to a point in which you can understand most native media outside of very specific things like very slang-heavy conversations in movies. ‍Crosstalk is also a great thing to do no matter your background. Production is a whole different thing, though. Even though you’ll be able to understand most things thanks to the similarity of the vocabulary and grammar, you still need to specifically acquire the words, expressions, and the grammar of the new language. You'll still learn to speak the language faster than somebody who doesn't know another Romance language, but don't expect your speaking to improve nearly as fast as your understanding. Even if you can understand most things after a few dozen hours of input, you’ll still need to get a few hundred hours of input to be able to have conversations without too much trouble.