It seems that your microphone is configured to play the data additionally. I have no English Windows, therefore I can't tell you the exact text.
Do the following:
1) Click the microphone button in PhonerLite with additionally pressed Ctrl key.
2) The windows sound dialog should appear. From now on that all has nothing to do with PhonerLite.
3) select your recording device and press the property/settings button (I don't the name in English Windows)
4) A new dialog opens with several index pages. In my Windows version the second page contains a setting to use the microphone device for playback too. Just check the pages if you see such setting. That option should be NOT checked.

If you don't have a phone call and activate manually microphone and speaker in PhonerLite, you have activated the sound test. Then you should hear yourself.