When we ask Google what the temperature will be tomorrow or Siri how to wash a sweater using our voice, we are doing voice search. Voice search describes searches performed on a search engine using oral language. These searches are performed with a voice assistant.

These are the main voice assistants and devices with which they are compatible:

Apple Siri - iPhone, iPad, iPod

Google Assistant - Google Home, Google Now, Pixel Smartphone, Android 6.0+ devices, iOS and Android apps

Microsoft Cortana - Apps for Windows 10, Windows Phone, Xbox One, iOS and Android

Amazon Alexa - Echo

Google search results depend on many factors other than the keywords entered, namely your previous searches. That is, Google identifies search patterns to deliver the best results based on what the user is looking for. This concept is known as semantic search and means that Google is refining understanding with regard to user searches.

For example, if I search for "Porto art exhibitions" on my smartphone while I am at Porto, and I have already done several other research on events in Porto, Google can realize that most likely I want to receive results on art exhibitions in Porto instead of art exhibits about Porto.

Voice searches are mostly done on mobile devices, which means that the results presented will also be ideally mobile-optimized sites. Thus, if in the last years it has become almost essential to have mobile-friendly sites, with the increase of voice searches it becomes mandatory to have sites optimized for mobile devices.

When optimizing your site, keywords should also be optimized specifically for voice search. This is because users do not search the same way when they write or when they use voice. In a voice search, the sentences are almost always placed with colloquial vocabulary and in the form of a question.

In the same way, the content of the sites should also be written in a more conversational tone. As a rule, voice search is done while the user is on the move or needs a quick response to a day-to-day question, so using simple and accessible vocabulary can be beneficial.

Lastly, defining demographics of the target audience will be even more important for SEO. Younger users are much more comfortable with voice searches than older ones. That is, companies targeting older audiences should target keywords with "writing pattern," while companies targeting younger audiences should use keywords with "voice pattern."