"If anyone thinks himself religious but does not bridle his tongue but deceives his own heart, this man's religion is worthless..."
A couple questions to help you evaluate whether or not your tongue is out of control...
1.) Are you nasty?
James 3:8-10, "But no one can tame the tongue; it is a restless evil and full of deadly poison. With it we bless our Lord and Father and with it we curse men, who have been made in the likeness of God; from the same mouth come both blessing and cursing. My brethren, things ought not to be this way."
The word for curse doesn't refer to profanity, but personal abuse. This is beating people up with your tongue.
Do you use your words to hurt others? Do you use your speech as a weapon? Do you say unkind things about other people? Is your speech nasty?
2.) Are you hyper-critical?
James 4:11, "Do not speak against one another brethren. He who speaks against a brother or judges his brother, speaks against the law and judges the law; but if you judge the law you are not a doer of the law but a judge of it."
Spurgeon describes the attitude of the man James is talking about, "Things that he would reckon vices in any other man are virtues with himself. If he could see in another man the selfsame action which he has just performed - if another could be the looking glass of himself - oh how he would thunder against him. He is the very first man to noice a little inconsistency. He is... the most upright of thieves, the most tremendously generous of misers; the most marvellously holy of profane men. While he can indulge in his favorite sin, he is for ever putting up his glass to his eye to magnify the faults of others."
Do you constantly speak about the faults of others, not because you are seriously and earnestly concerned about their good but just because you enjoy doing so? When you get together with your families do you spend a good deal of your time picking others apart? Think about the conversations you had yesterday, what did you spend most of your time talking about?
3.) Is your speech sick?
Ephesians 4:29, "Let no unwholesome word proceed from your mouth, but only such a word as is good for edification according to the need of the moment that it might give grace to those who hear..."
The word for unwholesome describes speech that is unhealthy, unproductive, corrupt, harmful, poisonous, destructive...It's the kind of speech described in verse 31, "bitter, mean, wrathful, vindictive, angry, clamorous, slanderous.
Does your speech help others grow? Is it fitting? Does it encourage others and give them strength? Or does it do just the opposite?
4.) Are you a dirty talker?
Ephesians 4:4, "...and there must be no filthiness and silly talk, or coarse jesting, which are not fitting but rather giving thanks..."
5.) Are you a liar?
Colossians 3:9, "Do not lie to one another since you laid off the old self with its evil practices..."
If you have more, please add...