Downloading MLSwitcher 2.1 for Mac from the developer's website was possible when we last checked. We cannot confirm if there is a free download of this app available. This Mac app was originally designed by Bluezbox Software. We recommend checking the downloaded files with any free antivirus.
From the developer:
MLSwitcher allows the ability to assign individual modifier combinations for every input language. It makes switching between input sources context-less and thus more efficient. Windows-like key combos for changing input language.
You may want to check out more software for Mac, such as MLSwitcher2, which might be similar to MLSwitcher.