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.

Mikael Korpela

Show language flags at “My sites” list in WordPress admin bar. Handy with multisite installation when you have blogs with the same name but their locale would be different. With this plugin you’ll be able to see the difference between them.
<a href="http://www.mikaelkorpela.fi/volunteering/" rel="nofollow ugc">Donations</a> are totally welcome, I’m spending most of my working time on open source and volunteer projects.
Plugin uses <a href="https://github.com/gosquared/flags" rel="nofollow ugc">GoSquared’s Flag Icon Set</a> (<a href="https://github.com/gosquared/flags/blob/master/LICENSE.txt" rel="nofollow ugc">MIT License</a>). Hooray for them!
Plugin source code at <a href="https://wordpress.org/extend/plugins/admin-bar-languages/" rel="ugc">WordPress repository</a> and at <a href="https://github.com/simison/WP-admin-bar-languages" rel="nofollow ugc">GitHub</a>.

Admin bar languages

Show language flags at "My sites" list in WordPress admin bar.

Cache Translation Object vs Admin bar languages