Knowing how katakanization works is an important practical skill for native English speakers who study Japanese. My wife, who's originally from the United States and now is a fluent speaker of Japanese after living in Japan for 15 years, still struggles to pronounce one of her home country's most well-known brands - 'McDonald's,' which in Japanese is マクドナルド (makudonarudo). Japanese words that even the most proficient learners of the language find the hardest to pronounce can be, ironically, the ones borrowed from their own native tongue.