"Caution: The default key provided by SpeechRecognition is for testing purposes only, and Google may revoke it at any time. It is not a good idea to use the Google Web Speech API in production. Even with a valid API key, you’ll be limited to only 50 requests per day, and there is no way to raise this quota. Fortunately, SpeechRecognition’s interface is nearly identical for each API, so what you learn today will be easy to translate to a real-world project."

Sir, since the Google Web Speech API cannot be used in production, what is the alternative for it? I mean how can I use the speech recognition then?