Answer: Speech recognition system.
Answer analysis: Speech recognition systems use recognizable words as a form of audio data input. Speech recognition is a technology that converts voice signals into text information, which allows users to interact with computers or other devices through voice.
In this system, the user's voice is captured and converted into digital signals, which are then analyzed and processed by complex algorithms to identify the words and phrases in it and convert them into readable text form.
The development of speech recognition technology is closely related to machine learning, especially deep learning.
Modern speech recognition systems are usually built using multi-layer neural network models, which are trained with a large amount of voice data to learn how to map voice signals to corresponding text representations.
With the continuous advancement of technology, the accuracy and robustness of speech recognition systems are also constantly improving, enabling them to play an important role in various practical application scenarios.
Therefore, for the blanks in the question, filling in "speech recognition" is the correct answer.