First, the language part, then the story.
It's commonly known that many Asian languages (such as Chinese and Japanese) don't have the typical [r] and [l] sounds that we have in English, and that native Asians learning English as a second language often mix up the two and/or struggle to make them sound different at all. Many can't even hear the difference.
This fact is often used for jokes in television and movies, such as a Japanese person intending to say, "clap" but who instead says, "crap." There are cruder examples, but I'll spare you.
According to our favorite online encyclopedia, the Japanese R is pronounced much like a soft Spanish R, where you flap your tongue against the palate behind your teeth. It's not at all like the English R. Plus, Japanese has no comparable L sound.
The article also states that the Chinese "R" really isn't one in the English sense. Instead, it's a "voiced retroflex fricative," which means it's more of a [zh] sound than an [r] as we'd know it. So again, Chinese people have no context for the English [r] and [l].
If you've lasted this long, you get to have the funny story part:
My maiden name is Luthy. (Pronounced like "Lucy" with a lisp. Not Lutchy. Not Loochy. Not Lutty. LUTHY. Got it? Good.)
As I've mentioned probably six hundred times, my dad has a Ph.D. in linguistics and taught at BYU until his recent retirement. He often had foreign students in his classes.
An Asian student once turned in a paper on this very concept: the difficulty in pronouncing [r] and [l] for Asian speakers of English.
I have no idea how good the paper itself was, but this student apparently also struggled with the problem and needed to brush up on distinguishing between the two sounds . . .
because the top of his paper listed his teacher as "Dr. Ruthy."