From Buddhism Nun:

Purify Speaking Karma – The Art of Speaking

Less complaining – more Tolerance.
Complaining brings the hate, tolerance brings the Wisdom.

Not being sarcastic – show Respect
Sarcastic puts people down, respect helps understanding each other.

Not to attack other people – but show more care in speaking. Attack creates damage for both – care and friendship

Not being strict in conversation – but show option to communicate. Being strict makes people have no choice and creates distance. Option brings people to trust your leadership.

Less judgement – more encouragement. Judgement creates the war from our heart. Encouragement helps people develop their potential.