Hello!
I would like to implement the script for you.
I assume you need to recognize speech, not songs.
Probably, existing English speech recognizers will good enough at your task. In this case, the price of the script is 30$.
Otherwise, I will need to prepare a lot of samples with and without the word 'hello', build, test and tune some models. It costs 80$
I have experience in Speech Recognition with old pocketsphinx and new DeepSpeech.
Best regards, Nikita Furin.