Everyone living in a country that’s using a cyrillic script knows the pain of having to work with a cyrillic URL in Firefox, having to switch layouts when typing an address, all the SEO implications and just how plain ugly it is to have mixed scripts in your “pretty” permalinks.

One solution to this is to edit your permalinks to something sane while creating the post.

Ain’t nobody got time for that.

There are 3 plugins I’ve used in the last couple of years with varying levels of success.

1. Cyr3Lat(Cyr to Lat enhanced) – Works great for the most part, goes through all your previous posts and transliterates any cyrillic characters. Unfortunately it doesn’t like WPML and the end result is completely messed up URLs. Not irreversible but still kind of annoying. The last update(as of the time of writing this – January 2017 ) was more than two years ago. Looks like there is no activity from the author in the support forums either.
2. Bulglish permalinks – targeted specifically for bulgarian, the transliteration for other cyrillic languages will probably be close enough but probably not 100% accurate. This one changes the permalinks only for posts, published after its installation. In other words – it doesn’t scan and fix your old posts’ slugs. Also, it appears to have an issue with multisite installs, although I’ve tested it only on one site(didn’t work at all), so it *may* have been a site issue. I doubt it though. The author is active(as of Jan 2017) and seems to respond to support threads. It’s a great, really simple and light plugin to activate on new installs and forget about.
3. WP Translitera – Found this one recently when both of the above refused to cooperate on a site I was working on. The author responded to my request for bg_BG locale within a couple of days and the plugin seems to get updates regularly. Also, unlike both of the above, this plugin has a very simple settings page, containing a section for converting the slugs of your previous content(post, pages etc.) and a couple of settings(checkboxes) which honestly I haven’t used or tested yet with the exception of the ‘Use forces transliteration for title’. I’m not sure what forces it uses but this setting fixes the WPML issue(that same one I mentioned for cyr3lat).