Adding a 2nd language in a premade site

Hello,

First of all, I would like to thank you for this wonderful plugin.

I’ve already searched the support page to check for a similar problem as mine but I haven’t found any.

I have a website in french, with a lot of pages and articles, posts and stuff. I want to add an arabic laguage (RTL). the problem is whenever I add french as 1st language, the content of the site goes rogue (unaligned menus etc ..) and the landing page doesn’t load.

FYI: I’m using WordPress 4.4, Betheme and an offline/intranet usage.

thanks in advance.

https://www.ads-software.com/plugins/polylang/