johanee

On every pageload a localized WordPress site spends a huge amount of time setting up the translation (l10n) object. Startup for a localized site can be almost four times slower than an untranslated one.
This plugin stores the translation object between pageloads so it only has to be created once, resulting in significantly better performance (performance graph included with screenshot).
Plugin supports caching multiple languages (if you use a multi-language plugin).
Available storage: Plain file, APC (Alternative PHP Cache), or SHMOP (Shared Memory)

Cache Translation Object

Substantially increase performance of localized WordPress by caching the translation (l10n) object. Supports multiple languages.

A.D.

Sometimes we want the front end of our blog to be translated for the users, but keep the backend admin panel in English. Admin in English with Switch does just that. It lets you switch your backend administration panel to English from admin toolbar, even if the rest of your blog is translated into another language. This plugin allows turning English language on and off for each user’s back-end independently.
For more information about original Admin in English plugin please visit https://wordpress.org/extend/plugins/admin-in-english/ page.

Admin in English with Switch

This plugin is an extended version of Admin in English plugin (v1.2) developed by Nikolay Bachiyski. See the Description for more details.

Cache Translation Object vs Admin in English with Switch