As some of you already knows, some Indian symbols are making a crash in iPhone.
Why This is Happening
The problem occurs when your device try to render certain sequence of Telugu characters in iOS 11 and macOS High Sierra. Extended report.
So How to Fix This Problem
It seems the problem is iOS 11.2 — and High Sierra 10.13. — exclusive. If you downgrade your devise or update to beta version(e.g. iOS 11.3 beta), the problem will gone.