English themes on a foreign language version of WP

Hi I've installed a Korean language version of WordPress 3.9. It's the full Korean version not intended to switch languages. My question is about themes with this install. I'm confused if I have to pursue multilingual themes or not. Everything looks find in 2014 theme but I'm wondering if I go to a more premium one intended for English, will I run into problems. Searching for 'multilingual themes' doesn't turn up much. Thanks.