Voice recognition software uses a combination of complex algorithms and machine learning techniques to understand and respond to human speech.

Speech to text works begins by recording your voice and then breaking it down into smaller parts called "phonemes." Phonemes are the individual sounds that make up words, such as "b," "a," "t," and "s" in the word "bat."

Once the software has broken down your speech into phonemes, it compares them to a set of pre-recorded phonemes in its database. The software uses a process called "pattern recognition" to find the closest match between your speech and the pre-recorded phonemes. The more sophisticated the software, the more phonemes it can recognize.

Once the software has found a match, it can understand what you said and respond accordingly. For example, if you say "what is the weather like today?" the software will recognize the phonemes and understand that you are asking for the current weather conditions. It can then retrieve that information from the internet and provide you with an answer. 

In addition to understanding individual words and phrases, voice recognition software can also learn to understand your unique speech patterns, such as your accent and pronunciation. This is done through a process called "machine learning," where the software is trained on a large dataset of speech samples and learns to recognize patterns and improve its accuracy over time.

Overall, voice recognition software is a complex and sophisticated technology that allows computers to understand and respond to human speech, making it a powerful tool for many different applications such as voice assistants, accessibility, and more.