After reading the specifications pdf found here:
http://www.lg.com/au/support-product/lg-27MP67VQ-P
I found no mention of this monitor having speakers.
It does however have audio inputs and audio outputs. For instance you could run an HDMI cable from your PC to the monitor and then plug a set of external speakers or headphones into the monitor for sound.
Another option would be to run 3.5mm analogue audio cable from your pc to your monitor and then use the audio output to power your headphones or external speakers.
Then finally you can always run the 3.5mm analogue audio cable directly from your pc to your headphones or a set of external speakers.
The reason for the 3 different choices is sometimes its preferable for wire...