Since Permalinks that contain Cyrillic may cause problems on some server setups, this plugin will work around this problem by updating the automatic Post Slug generation code. In this way, posts which have a title in Cyrillic will have permlinks transliterated in Latin characters.

Cyr2Lat Slugs

Converts Cyrillic letters in post slugs to human-readable Latin phonetic equivalent.

Themeisle

webcraftic

Note: This plugin is no longer being actively developed, and we recommend switching to <a href="https://wordpress.org/plugins/cyrlitera/" rel="ugc">Cyrlitera</a>, a more advanced version with expanded features and customization options.
Transliteration is the process of converting characters from one writing system to another, such as converting Cyrillic symbols to Latin. Because most web software and URLs are designed around Latin characters, using Cyrillic or other non-Latin symbols in links or file names can lead to unreadable URLs, accessibility issues, and even broken links. Transliteration ensures your URLs and file names remain clean, readable, and compatible across all platforms.
This plugin automatically replaces Cyrillic, Georgian, Turkish, and other supported characters with Latin equivalents to create clean and readable URLs for posts, categories, taxonomies, products, and custom post types. It also fixes incorrect file names by removing unsafe characters and transliterating them during upload, helping prevent 404 errors and broken media links.
<h3>Examples</h3>
Cyrillic URL before transliteration:
<pre><code>https://example.com/%D0%BF%D1%80%D0%B8%D0%B2%D0%B5%D1%82-%D0%BC%D0%B8%D1%80
</code></pre>
Same URL transliterated to Latin:
<pre><code>https://example.com/privet-mir
</code></pre>
Incorrect file names before transliteration:
<pre><code>%D0%BC%D0%BE%D0%B5_image_290.jpg
A+nice+picture.png
</code></pre>
Readable transliterated file names:
<pre><code>moe_image_290.jpg
a-nice-picture.png
</code></pre>
By using Latin-based file names and URLs, you avoid issues with encoding, broken links, and unreadable paths. This plugin performs the transliteration automatically each time a file is uploaded, ensuring your media library stays clean and consistent.
<h3>Features</h3>
<ul>
<li>Automatically transliterates URLs for posts, pages, categories, tags, and custom post types</li>
<li>Preserves existing URL structure while making it readable</li>
<li>Transliterates attachment file names</li>
<li>Removes unsafe or problematic characters from file names</li>
<li>Supports Russian, Belarusian, Ukrainian, Bulgarian, Georgian, Greek, Armenian, and Serbian character sets</li>
<li>Compatible with Advanced Custom Fields, Asgaros Forum, and BuddyPress</li>
</ul>
<h3>Advanced Transliteration Features</h3>
If you need more advanced transliteration features, consider upgrading to <a href="https://wordpress.org/plugins/cyrlitera/" rel="ugc">Cyrlitera</a>.
Unlike Cyr to Lat Reloaded, Cyrlitera offers a user-friendly interface that gives you full control over how links are transliterated. It also allows you to roll back converted URLs, create automatic redirects from old URLs to new ones, and help eliminate broken links across your site.

Cyr to Lat Reloaded – Transliteration of Links and File Names

I got a lot of 404 pages, and I don't know how to restore old URL

Plugin is change old permalink for all posts

Convert Cyrillic, Georgian and Greek URLs and file names to readable Latin characters. Works on slugs, attachments and taxonomies — no code needed.

Cyr2Lat Slugs vs Cyr to Lat Reloaded – Transliteration of Links and File Names