Do you know people are listening to you even if you are not aware that they are. We are all on display. When you swear and then praise the name of Jesus in the next breath it causes your witness of a changed life to be brought into question. If we are dying to self-daily, we will become more Christ like. One of the fruits of the spirit it to have self-control. The tongue is ours to control and what comes out of it. Does that make us perfect no.
Colossians 3:8-9 But now ye also put off all these; anger, wrath, malice, blasphemy, filthy communication out of your mouth. 9 Lie not one to another, seeing that ye have put off the old man with his deedsGalatians 5:22-23 But the fruit of the Spirit is love, joy, peace, longsuffering, gentleness, goodness, faith, meekness, temperance: against such there is no law.
If you are struggling as a Christian with using profane language then repent, ask Jesus to help you and put your faith in Jesus by believing that you do not need to do that anymore because this is something that Jesus has already died for on the Cross. Victory is yours, thank you Jesus!