I agree with you in the sense that English people do pronounce in some situations those phonemes (/pw/, /bw/, or /fw/), but I think that Priotr's affirmation refers to only English syllables, since all  the examples we can find with these syllables are words from languages.  Maybe he should have been more concrete in his affirmation, but from my point of view it is correct, if we separate English words from imported new words.

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Yes, Piotr's dissertational affirmation is correct. But we native-English-speakers with an education do know about those exceptional borrowings.

 

To repond, yes, my native-speakerness pronounces it Portoreeko and not Pwertoreeko. Iowa has a Buena Vista, and yes, it's done as bad as we do Nevada (which of course means we know better, but obey the rule about how native-speakers pronounce it).

 

I don't think Poles do Warsaw as Wore-Saw. Or Crack-cow. But that's how native-speakers of Midlands American English do it.

 

Mark.