How can I listen for a keyword and then when the keyword is said and then record the audio afterwards until I stop talking?

I am trying to create a Siri-like thing that will listen for a keyword and then start recording when the word is said and then when there is no speech for 3 seconds it will stop recording. After this, it will convert that audio recording to text and then the rest of the code will run using the text as input.

Thanks in advance guys

PS: Please just send the code so I can copy and paste it. Thank you, don't waffle