colinleroy

This plugin has no setting or UI. It just does one thing : use the php-gettext library to handle translations. This results in much faster translation than using the default PHP gettext implementation of WordPress.
If the extension is not available, the plugin will simply do nothing.
You can verify that the plugin is working by looking for an HTTP header: X-Native-Gettext: 1, that will be sent as soon as a string will be translated by the native library.
If your WordPress install is in English, this plugin has no purpose. Otherwise, it can help speed up your install quite a lot.
Requirements: 
– php-gettext 
– OS-level support for the locale(s) you want to translate to.

Native Gettext for WordPress

Great Plugin.

It does one job and it does very good!

With the help of the Query Monitor Plugin, I was able to measure a drop of almost 45% of PHP memory usage using "Native Gettext for WordPress" for a simple Dashboard-request.
Really cool.

The plugin author is answering friendly and helpful to support requests.

Fast & Friendly

No problems found, after testing on several sites. My sites are all heavily dependent on fast loading of text domains, and all have the PHP gettext extension. PHP 8.0 and 8.1.

However, may not work in combination with other WordPress plugins overriding load_textdomain.


Works as it says, fast

A very light wrapper plugin that uses the native gettext library for faster localization.

Bjoern

WP Performance Pack is your first choice for speeding up WordPress core the easy way, no core patching required. It features options to improve localization performance and image handling (faster upload, reduced webspace usage). Combined with CDN support for images, both on Frontend and Backend, this offers similar image acceleration as <a href="http://jetpack.me/support/photon/" rel="nofollow ugc">Jetpack’s Photon</a>.
<h4>Features</h4>
Improve localization performance
Translating WordPress is slow and uses much memory because by default WordPress loads all translations upon each request. WPPP improves performance and memory usage by using native gettext or dynamic loading of translations. If an object cache is installed optional caching improves performance even further.
<ul>
<li>Use of PHP gettext extension if available.</li>
<li>Dynamic loading of translation files, only loading and localizing used text.</li>
<li>Disable Backend localization while maintaining frontend localization (with optional override by user)</li>
<li>Caching of translations to further improve performance. A persistent object cache has to be installed for this to be effective.</li>
</ul>
Improve image handling
Create intermediate image sizes on demand not on upload.
<ul>
<li>Don’t create intermediate images on upload, instead dynamically create intermediate images when accessed.</li>
<li>Choose to save intermediate image sizes or to recreate them upon each access. Created images can be saved into a folder different from the original images folder.</li>
<li>Use EXIF thumbnail (if available) as source for thumbnail images. This improves memory and cpu usage as the source for the thumbnail is much smaller.</li>
<li>Adjust quality settings for intermediate images.</li>
<li>Regenerate Thumbnails integration: Hook into the thumbnail regeneration process to delete existing intermediate images. Supported plugins: <a href="https://wordpress.org/plugins/regenerate-thumbnails/" rel="ugc">Regenerate Thumbnails</a>, <a href="https://wordpress.org/plugins/ajax-thumbnail-rebuild/" rel="ugc">AJAX Thumbnail Rebuild</a>, <a href="https://wordpress.org/plugins/simple-image-sizes/" rel="ugc">Simple Image Sizes</a></li>
</ul>
Disable WordPress default widgets (BETA)
Really disable WordPress’ default widgets. Other plugins which allow you to disable WordPress default widgets only hide them, but the widgets’ files will still be loaded. WPPP really removes the widgets: Files of disabled widgets won’t get loaded.
CDN support
<ul>
<li>Serve (dynamically generated) images through CDN. Applies to all images uploaded via media library both on frontend and backend. No need to save thumbnails locally.</li>
<li>Fallback to local serving if CDN fails to return a valid response.</li>
<li>Dynamic image links: Image urls are generated dynamically when displaying post content.</li>
<li>Supported CDNs: CoralCDN, MaxCDN, Custom</li>
</ul>
Change or deactivate WordPress features
<ul>
<li>Disable header elements, such as generator name, feed links and more</li>
<li>Change heartbeat settings</li>
<li>Disable edit lock</li>
<li>Disable emoji support</li>
<li>Use persistent database connection</li>
</ul>

WP Performance Pack

Boost WordPress performance: Faster localization, (on the fly) dynamic image resizing and CDN support for images.

Native Gettext for WordPress vs WP Performance Pack