We read in the OT about people like Abraham and Samuel being able to hear God speaking to them. How could they hear God’s voice like that? If you hear God’s voice like that today you will be called mentally ill. What does the Church say about this?
This might be helpful catholic.com/quickquestions/what-is-a-locution
One of the ways God speaks is through his Church. The Church is the mouthpiece of Christ.
Look to the legitimate authority of the Church.
Some have had locutions as pointed out by frizzgrig.
Docility to the Holy Spirit is another way to hear God’s voice. A very short and powerful book has been written on the subject of hearing the voice of the Holy Spirit by Jacques Phillipe titled In the School of the Holy Spirit.
The website says: “Guided by the magisterium of the Church, the sensus fidelium knows how to discern and welcome in these revelations whatever constitutes an authentic call of Christ or his saints to the Church.”
How did the magisterium of the Church guide Abraham and Samuel?