The difficulty is that the rolling R sound is not found in a lot of english, and the L sound technically doesn't exist in Japanese. So unless you have a dextrous tongue, you will be unable to pronounce one or the other.
When I learned katakana, I spent more time facepalming than learning the new words. I remember my professor writing down KA RU GA RI, and I was sounding it out in my head. After a couple seconds, I asked her "is that Calgary? =|" and she was "Hai!", much to my disdain... Katakana is the perfect example of how "good" Japanese is at adopting words in other languages.
When I learned katakana, I spent more time facepalming than learning the new words. I remember my professor writing down KA RU GA RI, and I was sounding it out in my head. After a couple seconds, I asked her "is that Calgary? =|" and she was "Hai!", much to my disdain... Katakana is the perfect example of how "good" Japanese is at adopting words in other languages.