sound proof

Hi! We've recently moved into a mid-terraced Victorian cottage. We can hear our neighbours talking through the walls, even when they're not talking particularly loudly (luckily they're decent neighbours). Has anyone had a similar issue and what have you done that was effective - and at what...

Firstly, sorry if this is in the wrong place. I'm new here! I've just bought a new build semi detached for £250,000. My neighbours house is about 30cm lower down than mine since our houses are built on an incline. I know it's a semi, I expect to hear some noise, they have a piano and i can...