Is there anything in history that could explain why Portuguese had a very Russian sound to it. Were slavic countries at anytime a big part of Portuguese history?
I understand they're different languages and origins. I understand the similarities are the hard vowels. I am curious if there is a known reason why Portuguese differs from other Latin based languages so much and had a slavic sound and is there anything in history that could partially explain it?
I know you've already gotten some general answers, and they're all pointing in the right direction. However I wanted to add my own as a linguist who actually studies this specific kind of thing:
It's not the language; It's you. That Portuguese has a Russian sound to it is subjective. Yes, there are some sounds that are common between the two languages, but then there are sounds that are common between many unrelated languages. In this case, it's really just your own notion, and not one that everyone would feel to be true.
It's the same thing as how people in certain cultures think German sounds "hard" or "ugly"; It's not something inherent in the language, but rather just subjective judgements (which may often be culturally motivated).
May i ask as to where you got the idea that portuguese differs from other latin languages?
No. If you want to hear a Romance language that really does have significant Slavic influence, check out Romanian -- this is a link to a PDF. There's nothing especially weird about Portuguese in the Romance family, although I do get where you're coming from with the Slavic thing. I think it's just that Portuguese looks like Spanish, but doesn't sound like the Spanish you (well, I) learned in high school that throws people for a loop.
I can't speak as to the historic part of things, but Portuguese and Russian are very distantly related. They are both Indo-European languages, with Russian belonging to the Slavic sub-family and Portuguese belonging to the Romance sub-family (itself a sub-family of the Italic sub-family, which could potentially be part of a larger Italo-Celtic sub-family). The Indo-European language family itself contains languages as different as Hindi, Icelandic, Gaelic and Albanian. Because of this, Portuguese and Russian will possess a number of inherent similarities, most obviously found in common words. For example, the Portuguese word for mother (I believe, mãe) stems from the same Indo-European root as the Russian word for mother mat'. The similarity is even more striking if we compare the Latin mater to mat'. Furthermore, Russian has a number of loanwords from Latin, or neologisms derived from Latin roots (and also Greek roots), so other similarities could arise from this avenue. Again, both Portuguese and Russian may share loanwords from other languages, namely English.