Microphone has nothing to do with SPEAKER. Two different devices.
Look on the SOUND Panel, double click the SPEAKERS your not on a new Panel with headers General Levels Enhancement and Advanced. Click on LEVELS, are they turned up to 100 and NOT a / through the speaker (meaning it is turned OFF).
Under Enhanced at the bottoms is a PLAY button called PREVIEW, if you see your SOUND panel as well and look at SPEAKER listed, when you click on PREVIEW does the LEVEL indicator to the RIGHT of SPEAKER increase? If so you MADE a sound happen, did you hear it?
If you can SEE your sending SOUND but still NOT hearing it, check where you plugged in both ends for your Audio.
At that point this is more IN PERSON service call, where you need...