What is a VUI(voice user interface)? how to use it and benefits! An exhaustive guide

calendar_today Jan 4, 2023| schedule 24 MIN READ


In the world of virtual assistants, voice-controlled devices have become very popular. From google assistants to Siri, voice-controlled devices have become household members. According to Google, over 41% of people own voice-controlled devices and have them as virtual friends.

But have you ever thought about the technology behind these voice-controlled devices? If you did, you must have come across the term VUI or voice user interface. IT enables users to interact with a device using voice commands.

With the help of a voice user interface, you don't need to carry devices with you yet have complete control. VUI is also present in virtual assistants where you give a command without using traditional methods.

Voice user interfaces in voice assistants are reshaping the human-device relationship. VUI also helps in rebuilding customer behavior in the field of eCommerce.

If you want to know what VUI is, how to use it, and its benefits, continue reading the article until the end.

What are Voice User Interfaces?

Voice user interfaces (VUIs) allow users to interact with a system by speaking or speaking commands. VUIs include virtual assistants such as Siri, Google Assistant, and Alexa. The main benefit of a VUI is that it allows consumers to interact with a product without using their hands or their eyes while focused on anything else.

Applying the same design principles to VUIs as to graphical user interfaces is impossible. Because there are no visual affordances in a VUI, users have no clear signals of what the interface can accomplish or what their alternatives are while looking at it. When creating VUI actions, it's critical that the system clearly states various interaction possibilities, informs the user of their capability, and keeps the quantity of information given to a minimum.

People are sometimes dubious of the intricacy that the VUI can grasp since they equate voice with interpersonal communication rather than person-technology interaction. As a result, for a VUI to succeed, it must have a strong understanding of spoken language and instruct users on what kind of voice commands they must use.  

Because of the complex nature of a user's interaction with a VUI, a designer must pay particular attention to how quickly a user might go overboard with expectations. The product is designed in such a basic, nearly featureless manner—to remind the user that two-way "human" communication is impossible. 

How Does a Voice Interface Work?

The merging of many Artificial Intelligence (AI) technologies, such as Speech Synthesis, Automatic Speech Recognition, and Named Entity Recognition, results in a voice UI. 

The VUI's speech components, powered by AI, are frequently kept in a private or public cloud, where the VUI processes the user's voice and speech. The gadget receives a response from AI technology, recognizing the user's purpose.

That's the foundation of a voice UI. Most businesses integrate a Graphical User Interface (GUI) and different sound effects into the VUIs to give the optimum user experience. The user can tell whether the gadget is listening, processing speech, or replying to them thanks to visuals and auditory effects.

What Technologies are used to create a VUI?

Automatic Speech Recognition

Automatic Speech Recognition (ASR) is a text-to-speech system that analyzes and processes human speech. ASR must filter out distracting acoustic sounds and recognize human speech instead of given audio input. It might be difficult due to audio distortions and streaming connection issues. 

Several underlying technologies, such as Gaussian mixture models (a probabilistic model) and deep learning with neural networks that process and distribute information to gather data, have been studied and utilized to construct ASR technology. 

The words identified by ASR are frequently not exact matches to things inside a user's intent. In these circumstances, enhanced entity matching is employed, which compares similar words or words with similar sounds and matches them to a VUI entity.  

Name Entity Recognition

Name Entity Recognition (NER) is a technique for identifying the underlying entity of words. Entities or semi-structured text can be a person, a subject, or something as particular as a scientific word, and NER can find them. When determining the value of an entity, NER frequently looks at the surrounding text or words.

ASR relies on NER to resolve words as entities. NER is very context-sensitive and requires extra information to identify things accurately. NER is sometimes dependent on past training and cannot accurately detect the entity of an input. 

Speech Synthesis

Using input text, Speech Synthesis creates an artificial human voice and speech. VUI completes the task in three steps. Input, processing, and output are the steps. Speech Synthesis is a text-to-speech (TTS) output in which a device reads aloud over a loudspeaker what was entered with a synthetic voice.

These AI systems study, learn, and replicate human speech patterns and change intonation, pitch, and tempo. Intonation is how a person's voice rises and falls as they talk. Emotion, accent, and diction are all factors that influence intonation. Pitch is the tone of a person's voice unaffected by emotion. 

Pitch is a squeaky or deep voice with a high or low pitch. Cadence is the fluctuating pitch of a person's voice as they talk or read. To generate an effect on their audience, a public speaker will shift their cadence by dropping their voice throughout a declarative statement.

 Once the user data has been collected and processed, these technologies will apply machine learning to better themselves and the VUI. The clouds and technologies will determine the user's intent, and it will send a response via the application or device.

Intents & Entities

Voice commands consist of intents and entities. There are local intents and global intents. Local intent is when it asks the user a question in which they respond "Yes" or "No." A global intent is when a user has a more complex answer. When designing VUIs, you must consider different ways of saying commands to recognize the intent and respond correctly. 

 Five Principles of a good VUI

It isn't easy to provide people total control over their gadgets without requiring them to engage with them physically.

Let's look at some design elements to remember while creating a VUI.

  1. Well-defined target audience: A VUI solution that meets the demands of its target audience is more likely to engage and retain customers.
  2. User onboarding: Educating clients about the voice experience helps them acclimate.
  3. Physical elements: On your VUI device, include some physical features, such as a power button. It is to give an alternative to the device's spoken interface for engaging with it.
  4. Conversation flow mapping: Research the conversation flow to make your VUI user-friendly. When an IVR provides too many alternatives to pick from, for example, consumers may become confused and annoyed.
  5. Layered design: A voice interaction should be a discussion between the user and the gadget.

How to design a voice user interface

Step 1: Conduct user research

It will help if you find out the device persona you are targeting. After knowing who will buy your product, you can determine the features and skills your VUI device must contain.

Amazon Alexa is an excellent example of recognizing the device persona and then providing all that the consumers desire. It has various functions, from weather forecasting to managing smart gadgets.

Step 2: Learn about the anatomy of voice commands.

When a user offers an AI assistant a voice command, it consists of three parts:

  1. Intent: This refers to the user's voice command's goal. Intent can be a high utility. For example, requesting that certain music be played – or low utility – provides more ambiguous input, requiring the AI to ask follow-up inquiries.
  2. Utterance: The way a user expresses a voice command to do a certain job.
  3. Slot: This is either an optional or necessary variable in voice interaction. The slot will be the date if a user wishes to reserve a hotel stay on a specific date.

Step 3: Perform a competitor analysis

Always consider how your rivals use automated speech recognition and voice technologies in their goods when building a VUI. It aids you in designing your product to meet client pain areas that your rivals have yet to address.

Step 4: Put your goods to the test.

Test the voice design and the speech interface. Perform a few trial runs within your firm or with outside contractors. It would help if you made sure that the vocal contact was natural. Nobody likes to feel like conversing with a robot, so make sure your VUI device simulates a real human dialogue.

Voice User Interface – Benefits and Drawbacks

Benefits of VUI

  1. More convenient than typing: Dictating is handier than text messages since it is faster.
  2. Easy to use: Not everyone is comfortable using technical equipment. However, users may use speech to ask VUI devices or AI helpers for a job.
  3. No use of hands: Speaking is far more practical than typing or tapping in various situations, such as driving, cooking, or while away from your device.
  4. Eyes-free: VUI offers a hands-free experience. When driving, for example, you may concentrate on the road rather than the gadget.

Drawbacks of VUI

  1. Privacy concerns: Some users are concerned about the potential for a VUI to violate their privacy.
  2. Inaccuracy and misinterpretation: Voice recognition software still has faults. The program cannot comprehend and grasp the linguistic context, resulting in mistakes and misunderstandings. Voice dictation for automated typing may result in mistyping since VUIs do not always distinguish homonyms, such as "there" and "their."
  3. Public spaces: Due to privacy and noise concerns, giving voice instructions to gadgets and AI assistants in public spaces might be difficult.


The Voice user interface went from recognizing a few words to speaking a million vocabularies in different accents and styles. It also focused on user experience design in the UX field. Many businesses are switching to the practical uses of VUI while combining graphical user interfaces. Voice assistants come in various shapes and devices. It helps in the smooth flow of lifestyles, work, and education. VUIs are created with the help of AI, automatic speed recognition, named entity recognition, and speech synthesis. With the use of machine learning, the interaction between the user and voice interface improves. It has many benefits, including in different sectors like eCommerce, education, and more. It is for sure that voice user interfaces are the future of AI.