What is speech recognition, and how does it work?

What is speech recognition technology?

Speech recognition, also called automatic speech recognition (ASR), computer speech recognition, or speech-to-text, is a form of artificial intelligence and refers to the ability of a computer or machine to interpret spoken words and translate them into text. Often confused with voice recognition, which identifies the speaker, rather than what they say, speech recognition software turns human speech into written language or computer commands.

How does speech recognition work?

Every device, from a phone to a computer, has a built-in microphone that picks up and records audio signals and speech samples. The speech-to-text technology then breaks down the recording, removes background noise, and adjusts the pitch, volume, and tempo of the speech. From there, it converts the digital information into frequencies and analyzes separate pieces of the content.

After speech recognition software processes the recording, it starts interpreting human speech. With the help of acoustic modeling, a crucial component of modern speech recognition systems, the program creates mathematical representations of different phonemes (basic units of sound) that distinguish one word from another and makes hypotheses about what the person is saying based on the context of the speech.

The software then generates word sequences that best match the input speech signal and writes the recording out in readable text. The user can then process the recognized transcription further and correct the mistakes or adjust accuracy.

As simple as the speech recognition process may sound, the software itself is pretty complex, involving signal processing, machine learning, and natural language processing. Moreover, the system processes information at lightning speed, way faster than a human being. However, the output accuracy may depend on the quality of the original recording, the complexity of the language, and the system application.

Speech recognition algorithms explained

Multiple speech recognition algorithms and computation techniques work in a hybrid approach and help convert spoken language into text and ensure output accuracy. Here are the three main algorithms that ensure the precision of the transcript:

1. 1.Hidden Markov model (HMM). HMM is an algorithm that handles speech diversity, such as pronunciation, speed, and accent. It provides a simple and effective framework for modeling the temporal structure of audio and voice signals and the sequence of phonemes that make up a word. For this reason, most of today’s speech recognition systems are based on an HMM.
2. 2.Dynamic time warping (DTW). DTW is used to compare two separate sequences of speech that are different in speed. For example, you have two audio recordings of someone saying "good morning" – one slow, one fast. In this case, the DTW algorithm can sync the two recordings, even though they differ in speed and length.
3. 3.Artificial neural networks (ANN). ANN is a computational model used in speech recognition applications that helps computers understand spoken human language. It uses deep learning techniques and basically imitates the patterns of how neural networks work in the human brain, which allows the computer to make decisions in a human-like manner.

Use cases of speech recognition

As a rapidly growing technology, speech recognition is used in various industries and improves automated processes, saving people’s time and creating convenience. Here are some of the common use cases of speech recognition:

• Navigation systems. Speech recognition software is often used in navigation systems and allows drivers to give voice commands to vehicle devices, like car radios, while keeping their eyes on the road and hands on the wheel.
• Virtual assistants. Voice-activated personal assistants are playing an increasingly important role in our daily lives. The speech-to-text feature enables personal assistants like Siri or Google Assistant on mobile devices to help you find the information you need or perform certain functions on your phone. Your Amazon Alexa or Microsoft Cortana works the same way; it interprets your request, answers your questions, or plays your favorite song.
• Healthcare. Automatic speech recognition is also used in the medical field, where speed and accuracy are critical. Doctors use this technology to convert speech into text for medical reports, clinical notes, and updating electronic health records. Speech recognizers also help improve clinical documentation, such as treatment plans and the accuracy of diagnoses.
• Call centers. Customer support call centers often use speech recognition systems to automate customer interactions. The systems analyze speech input and respond to customer requests, providing more time for human agents to deal with complex issues.
• Accessibility. Speech-to-text processing can help people with disabilities use technology and the internet. Individuals with limited mobility can control their devices using voice search, like answering phone calls or browsing the web.
• Language translation. Machine translation software also uses speech recognition programs to convert human speech from one language to another.
• Voice search. Speech recognition systems are also part of search engines and allow users to surf the web using voice commands.

Speech recognition, as a form of artificial intelligence, helps automate processes and improve efficiency and accuracy in many professional fields as well as our daily lives. Meanwhile, it continues to evolve, and we will likely see even more extensive use of this technology.

Differences between speech recognition and voice recognition

Speech and voice recognition are pretty closely related, often used side by side in devices. But at the same time, they are each a distinct technology and are often confused with one another. So let’s look at their differences.

Speech recognition refers to the process of a computer recognizing, understanding, and transcribing speech into readable written text. This technology is used in different professional fields and our daily lives and facilitates the process of dictation, transcription, or natural language processing. Speech recognition programs analyze the acoustic features of audio and voice signals, such as pitch, tempo, different accents, and other speech variables, to identify and transform word sequences into text.

Voice recognition, on the other hand, converts voice into digital data based on the user’s unique voice characteristics. This technology is a biometric system used to verify a person’s identity by analyzing the unique features of their voice, such as pitch, tone, and rhythm. Voice recognition is often used for security and personal authentication, such as unlocking a mobile device or accessing systems.

To sum everything up, speech recognition is a technology able to recognize speech and its distinct features like language or accents, while voice recognition is about identifying a specific person’s voice based on their unique voiceprint. Both technologies are very important when creating a natural interaction between humans and machines.

Is it safe to use speech recognition software?

The safety of speech recognition systems depends on several factors, such as software security measures and the context of use.

Speech recognition software safety ultimately depends on the vendor, so make sure to read the security policies before using it. Speech-to-text applications from reputable service providers are usually safe because they care about their users' safety and implement the latest security measures.

What you should be looking for in a trusted speech recognition service is ISO accreditations, NDA enforcement policies, and data encryption systems, ensuring the unfettered use and security of the system.

But, of course, like all technologies, speech recognition can also be vulnerable to hacking and malware. It is, therefore, essential to occasionally update your antivirus software and operating system to reduce the risk of security vulnerabilities. Stay vigilant and educate yourself in cybersecurity – this is the cornerstone of your online safety and protection against prying eyes.