> and their English mistakes are pretty uniform due to the specific differences between the languages, esp regarding prepositions and tense
This is not the case. Different people make different mistakes, as any exposure to a high-school level English class will allow you to discover. There's a case for clusters of similar errors, but then again any generalizing statement is true for a sufficiently high level of clustering.
That's a very strange view. Of course people with a native language will make similar mistakes when learning a new language. Swedish speakers have issues pronouncing "jump" ("yump" ) and cheap ("sheep") because the language doesn't really have those sounds. Because were and was is the same word in Swedish, that's also a common mistake.
"Their" referring to the group of Portuguese speakers that I know, not Portuguese people as a block. That implication came about due to you alone. The observation that you quoted is based on both my interaction with them, but also their interpretation and observation of themselves relayed to me in conversation(many of them are in the field of linguistics, so this type of thing comes up a good bit).
I can see how you could draw that conclusion from my post, however. I assure you there was no intent to generalize.
This is not the case. Different people make different mistakes, as any exposure to a high-school level English class will allow you to discover. There's a case for clusters of similar errors, but then again any generalizing statement is true for a sufficiently high level of clustering.