Langy 1.0 for Mac could be downloaded from the developer's website when we last checked. We cannot confirm if there is a free download of this app available. This free software for Mac OS X was originally developed by Nicolás Santangelo. According to the results of the Google Safe Browsing check, the developer's site is safe. Despite this, we recommend checking the downloaded files with any free antivirus software.
From the developer:
Langy is an open source Mac OS X application which helps you changing your keyboard language per app. You can select which language to use for your desired apps, and a default language to fallback and this program will automatically change it on focus.