Can't switch main language into Korean.

### Problem
On the main `semantic-ui.com` website, I can't seem to be able to switch the language into Korean.
I have noticed other languages work fine and also updates the html `lang` property. I am not sure if I am missing something but please let me know 👍 

### Env

- Chrome v73.0.3683.86
- Safari v12.0.3