Automatic repetition—with the option to repeat 1, 2, or 3 times—eliminates the need to keep pressing the “S” key. This is a very useful feature that allows for hands-free use.
I often listen to Language Reactor while doing household chores, specifically when using the “My Texts” section.
Another great suggestion—which I’ve mentioned here before—would be to add audio in both languages (in my case, English and Portuguese). This would be extremely helpful for studying the languages from both perspectives, especially if a “switch” function were included.