I’ve never tried removing language files since it always seemed like it could go wrong (it has been recommended as a space-saving measure for many years). Luckily, CleanMyMac X lets you choose what it removes, so it’s easy to avoid that one.
Joe Kissell recommends it (he looked into while writing Take Control of Maintaining Your Mac) and I trust him far, far more than any random person in a forum because he actually tests things carefully.