No there is no problem with transcribing what the person says - anything they say. the sin is theirs not yours. But if you are worried that transcribing their words will make you more likely to say those words and/or you find that in transcribing them you cannot stop saying them or you are making them your own then, it may indeed be prudent to stop doing that kind of work or chose another transcription, if possible.
You must always be careful and prudent in protecting your soul. That is wise, but don’t take it too far, for the Lord your God is with you and has given you the tools to do your work with. So if you feel that God has called you to this job, you are good at it and do it well or need to do it for the sake of your family etc. (discern this by praying - get into the habit of asking God about everything - he is your best friend. Check with him first). If the job is good then ask your best friend to be with you. Remember you can put on the armour of God each day and be protected. St Paul told us to ‘Stand your ground, putting on the belt of truth and the body armour of God’s righteousness’ in Ephesians 6:14 . You are not alone, God is with you helping you. And you can even make up for the other person’s sin of taking the Lord’s name in vain with this little prayer ‘Admirable is the name of God’ which mitigates God’s wrath on the person taking the Lord’s name in vain. We should always say this when we hear someone saying such things (or if we do). So you can put this work of yours to good use in reparation for the sins of others. You can also pray for the people who have used bad language by saying Hail Mary’s for them and so do further reparation for them. In this way your work is love of neighbour. God bless.
