Mouna or silence when practised as a yoga gives all good results for the mind ,body and soul.When mauna is practised for an hour a day the mind becomes very refreshed and more work will be achieved by the person.It should not conflict with one's daily duties or put other people in trouble.
Spiritually motivated silence is known a s mouna yoga.Ordinarily keeping silent would be called mauna but avoiding any type of communication is an advanced level with direct results.
It must be noted that when a person is silent forcefully out of anger or fear or any negative feeling is bad for health.
The obvious benefits of mauna are that one can avoid are gossiping,backbiting,exposing one's ignorance,talking to the point that one regrets later,spending away so much physical energy and also saving a lot of time.
Mauna yoga creates a kind of stillness of mind where one can be both peaceful and alert.