It's just a question of habit... and practice... and being able to hear the difference. It's a fun game I play with my students: "did I say lip, or did I say rip?" It gets even funnier when they say one of the l/r pairs and everybody's supposed to figure out which they said. The niggly detail is that the らりるれろ line of sounds aren't "Rx" they're an rl combined sound that sometimes sounds more like an 'l' and sometimes sounds more like an 'r' and almost always has a lot more *tongueclick* than the english l or r (Spain-style Spanish has a lot of tongueclick in it's 'r' sound, Mexican-style Spanish has much less)I think she pronounce "R" okay, of course she cannot pronounce "L" properly but none of us can, our tongue will not shape this way, we do not have this sound in Japanese. [/color]
And on the "rolled rs" topic, it's actually a pretty common sound for low-lifes in Japan. (Orrrrre) It was with that context that I found Matsuura's rolled-rs in Good-Bye Natsuo funnier than sexy. But everybody approaches a song with their own context (yay post-modern constructionism!) so if it's sexy to you, it's sexy. :cool