Apple first introduced Siri in October 2011, and the world (at least those who owned iPhones) fell in love with it. You could know the world was in love with it when it was featured in sci-fi movies here and there.
These days, Siri is available not just on iPhones, but also Apple TV, Apple Watch, and even Mac thanks to the recent macOS Sierra update. Though it is not enabled by default on your MacBook, supposing it is running the recent macOS Sierra.
How to enable Siri on MacBook
If you like, you can change the language Siri will use, based on gender and type of voice. You can disable Siri by following the steps above and unchecking the box next to Enable Siri.
Accessing Siri on your Mac
The third option is to press on Command + Space Bar to activate Siri.