How do you pronounce Louis in Japanese?

There isn't a single, universally accepted pronunciation of "Louis" in Japanese. Japanese doesn't have the same sounds as English, so it's approximated. You'll commonly hear it pronounced in a few ways, depending on context and the speaker's preference:

* ルイ (RUI): This is probably the most common and easiest way. It uses the katakana ル (ru) and イ (i). This pronunciation is fairly close to the English pronunciation.

* ルイス (RUISU): This uses the katakana ル (ru), イ (i), ス (su). This adds a "su" sound to the end, making it slightly closer to the English pronunciation for some speakers. This is less common than ルイ (RUI).

Ultimately, the best pronunciation depends on the specific context and the person you're talking to. ルイ (RUI) is a safe bet and easily understood.