What are some ways freedom of speech is limited? why are there limits to freedom to speech?

Well I would say now people are very sensitive and touchy and say stuff lf they feel attacked so many people don't say what they would like to say.

Or like by promoting radical terrorist ideas or by inciting riots which you can get in trouble for.

Because if you just said anything that was on your mind you could hurt people mentally, physical and emotionally.  

I hope this helps.