Performance

Problem:
The client is experiencing slow site response times of 10-12 seconds when using the WPML and String Translation plugins. The issue persists even after upgrading the server, enabling caching, and creating a staging site. Deactivating the String Translation plugin resolves the issue, indicating it as the source of the slowdown.
Solution:
We performed several steps to address the issue:
1. Ran the WPML troubleshooting option to "Cleanup and optimize string tables" at WPML > Support > Troubleshooting, and created the necessary custom language MO files at /wp-content/languages/wpml, which improved site performance.
2. Suggested cleaning up the database by following the steps outlined in this documentation. This includes installing a recommended plugin and running the cleanup process multiple times.
3. Provided a SQL query to delete untranslated strings from the WPML String Translation:

DELETE FROM wp_icl_strings WHERE status = 0;

4. Identified that the custom theme significantly increases load times when enabled. Recommended switching to a default theme like Twenty Twenty-Four, which reduced load times to about 2 seconds.
5. Noted an issue in the custom theme's code and provided the correct usage:

echo __('my-string', 'my-textdomain');

should be

_e('my-string', 'my-textdomain');

as per WordPress standards.

If these solutions do not resolve the issue or if they seem outdated, we highly recommend checking related known issues at https://wpml.org/known-issues/, verifying the version of the permanent fix, and confirming that you have installed the latest versions of themes and plugins. If the problem persists, please open a new support ticket.