To get the WordPress Multilingual (WPML) Yoast SEO Add-on (often referred to as the “WPML SEO” glue plugin) working correctly, you need to meet the specifications for both the core plugins and the bridge that connects them.
This is EXACTLY the same product as distributed by the developer. Sales Page
You cannot run the “Add-on” in isolation. It requires the following components to be active:
Yoast SEO (Free or Premium).
WPML Multilingual CMS (Core plugin).
WPML String Translation (Required for translating SEO attributes like titles and breadcrumbs).
WPML SEO (The specific “glue” plugin that provides the integration).
The environment must support the heavy lifting of both SEO analysis and multilingual processing:
PHP Version: 7.4 to 8.3 (PHP 8.2+ is highly recommended for performance).
WordPress Version: 6.6 or higher (Supports the latest two major releases).
Memory Limit: Minimum 128MB, but 256MB is the strongly recommended floor to avoid crashes during translation processing.
Database: MySQL 5.6+ or MariaDB 10.1+.
PHP Extensions: mbstring (for character encoding) and SimpleXML (for sitemap generation).
The addon bridges the gap between Yoast’s SEO engine and WPML’s translation engine to handle:
Multilingual Sitemaps: Automatically creates a single sitemap_index.xml that includes all language versions or separates them by domain/directory.
Hreflang Tags: Injects rel="alternate" hreflang="..." tags into the page <head> to tell search engines which language version to serve based on user location.
Breadcrumbs Translation: Syncs Yoast’s breadcrumb trail with the current active language.
On-Page Meta: Enables the translation of SEO Titles, Meta Descriptions, and URL Slugs via the WPML Advanced Translation Editor.
Schema.org: Translates structured data (FAQ, HowTo, Product schema) so search snippets appear in the correct language.
WPML Plan: This addon is only available to users with the Multilingual CMS or Multilingual Agency plans. It is not included in the basic “Multilingual Blog” plan.
Page Builders: Fully compatible with Elementor, Divi, and the Block Editor (Gutenberg) when used alongside Yoast.