macbre

This extension has been inspired by http://devel.kostdoktorn.se/cache-translation-object and gives up to 5x speed increase when using WordPress with “custom” (i.e. non English) localisation files.
MO object created by WordPress is cached and stored in the <code>/wp-content/cache/</code> directory and then used when loading localisations.

l10n cache

Improves site performance by providing caching for localisation objects (*.mo files).

Sergey Biryukov

Creates a separate tiny .mo file to use on a site front-end. Allows to save some amount of RAM on a shared hosting server.
Thanks to MAX for the original non-plugin solution and to AlexPTS for the idea.

WPLANG Lite

Creates a separate tiny .mo file to use on a site front-end.

l10n cache vs WPLANG Lite