You have to set up the microphone before using any speech recognition program on your Mac.
The macOS version of Siri can be used for sending very short messages and interacting with your computer, but it cannot be used for dictating passages of text.
In addition, the Siri voice interface used on iPhones and iPads was added to macOS Sierra in late 2016. These both allow you to dictate sentences and have your speech converted into text. and the commercial Dragon program from Nuance.the Dictation system built in to recent versions of the macOS.There are two main options for speech recognition on the Mac: