I know many people claiming that, including me. I speak both and have to say they have many sounds in common, indeed. Here's what I found out so far: 1. There are both types of Russian 'l' sound in Portuguese: normal (dark) l (л) as well as the soft one 'lh' (ль) 2. The 'r' sound is trileld in both 3. The 'sh'/ш sound is frequent in both and sounds harder than for example the English one. 4. There is a reduction of vowels - in Russian only to some extent though. 5. Russian sound ы exists in Portuguese in non-stressed e's like leitE, quE, etc. (a sound closest to English 'i' in (bid, sit, etc.) 6. One of sounds represented by 'e' (exatamEnte) in Portuguese is close to Russian 'e' /ye/ Let me know if you found anything else ;) Cheers!