In my case, I'm serving in a foreign language congregation and I'm fading. I think in some respects is harder, at least in my personal experience.
Being in a small foreign language congretation makes you have more parts, more responsibilities and you are easily noticed if you start missing meetings. Plus, in those kind of congregations tend to be more zealous elders and pioneers who are always telling you to go in field service with them.
But it's different if you're new in that congregation and you're moving to fade. In that case, you can tell the elders you need your time to adapt to the language.