Is it possible for you to elaborate your question a bit? For example, Are the counterpart that you are calling not able to hear you during phone calls or have the speakers on the phone stopped working? Also, have you been able to carry out a quick test of the speakers/microphone to see if the hardware works as intended? To do this Find and tap Settings > Support > Xperia Tests > Speakers & microphone.
Please do elaborate and I will do my best to assist you!