If you're using on your Samsung Galaxy S5, the app "S Voice" to input voice commands, it can happen that you receive no voice feedback. Voice feedback means that you will be informed about the result via voice after speking a voice command. If you do not receive voice feedback along with S voice on your Samsung Galaxy S5, this is usually because of the following setting: "Disable voice prompt"
So you can now enable this option for voice feedback on your Samsung Galaxy S5 within S Voice again. Please proceed as follows:
Open on the Samsung Galaxy S5 from the home screen the menu and then the app S Voice. After opening the app, tap the three-point icon at the top right, which will now open a small menu. Here you can see now the option "Enable voice prompt" . Tap an entry to reactivate the voice feedback of S Voice on your Samsung Galaxy S5.
If you enter voice commands in the S voice app, you will from now on get sound feedback from your Samsung Galaxy S5.