This is a weird thing because you'd be hard pressed to find two languages as similar as Spanish and Portuguese, and whatever this paper has to say on the topic it'd be inevitable that the English translation in the middle would be "lossy".
I sometimes get disappointed when people suggest that machine translation is a substitute for actually learning the languages. It's true that we have limited time in our lives to study languages, and the machine translations can be a quicker way to get the gist, or possibly open some doors. But go much beyond that, like claims I sometimes see that you can wear AR goggles and suddenly communicate like a native, and you set unreasonable expectations. Or perhaps imagine a world where the way to read Shakespeare is to put it through a machine and it tells you, "statistically, Shakespeare meant to say this". Is that really reading it?
Actually there are quite a few, if you include the variants spoken across the peninsula, Galician, Mirandese and Aragon are even closer to Portuguese than Spanish. :)
Yep, I was aware of some of those, not trying to defame the good people of Galicia or anything, just trying to say that Iberian Romance languages are all pretty similar, and notwithstanding many exceptions the probability of easily finding nearly 1-to-1 translations of any given text is much higher than for English where you would inevitably lose more information in transit.
My wife is Russian, and things she says about how Ukrainian sounds to her reminds me a lot of what Spanish speakers say about Portuguese. I don't know enough to say how similar that comparison is, but it passes the "neighboring regions that might have been more mutually intelligible 1000 years ago" test.
I sometimes get disappointed when people suggest that machine translation is a substitute for actually learning the languages. It's true that we have limited time in our lives to study languages, and the machine translations can be a quicker way to get the gist, or possibly open some doors. But go much beyond that, like claims I sometimes see that you can wear AR goggles and suddenly communicate like a native, and you set unreasonable expectations. Or perhaps imagine a world where the way to read Shakespeare is to put it through a machine and it tells you, "statistically, Shakespeare meant to say this". Is that really reading it?