Poedit

Poedit is a translations editor for translating apps and sites that use GNU gettext for localization. This includes most Linux programs as well as PHP or WordPress. All commonly used features of gettext are supported, including plurals, message contexts or extraction of translatable strings from the source code. Thanks to its distraction-free approach, you'll translate faster and easier with it. This is the full version of Poedit with all Pro features enabled. Poedit is intentionally spartan so that the the focus is on the translation you're working on. Just you and the translation, no distractions. Gettext can be tricky at times. One accidentally added % may break things if you're unlucky. Not to worry, though, Poedit checks for common problems and warns you.

Poedit suggests possible translations for you. It fetches the suggestions from a vast online database that contains hundreds of millions entries and, combines with your personal translation memory and adds state-of-the-art machine translation into the mix. And that's in addition to your personal translation memory that the app maintains. Developers can use Poedit to maintain their translation files (or templates) and keep them fresh. It may be too simple for more complicated projects, but most of the time, that simplicity comes handy. Poedit has dedicated support for WordPress themes and plugins.