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.
What's new in MLSwitcher
Possible fix for compatibility with macOS 10.14 (Mojave): request user permissions to use accessibility features.
The workaround for older version is to add open System Preferences, navigate to "Security & Privacy", open Privacy, tab, select Accessibility item in the menu to the left, add MLSwitcher to the list of apps and grant permissions by ticking checkbox.