It's called clairaudience. Research it, there are many ways to heighten this sense. Personally, I suggest using a pendulum to communicate with spirits (preferrably a guide) and ask them to speak their answers at the same time. Eventually you won't need the pendulum.
Here is a good link as to how to use a pendulum.
I don't believe in using pendulum boards. But for hard to spell/hear names, if you're not good at automatic writing, I suggest writing out the alphabet (widely spaced) on a piece of paper and the pendulum will "pull" in the direction of the right letter and then circle the letters. Then you can toss the paper afterward so it doesn't collect energy.
I personal cleanse my pendulum before and after I work with it, everytime. A simple way is by using either a candle or incense/smudge stick, hold it about 6-8 inches above the flame/smoke source and pray over it, visualizing the energy of the element passing through the pendulum and enveloping it. Mine pendulum circles stronger and stronger. I stop when the pendulum is circling very widely and quickly demonstrating to me that its energy is clean and the flow of energy within it is not blocked by any "gunk" making it a better conduit. Then I proceed with my work.