What does the future hold for voice search? If you search the web for these words – or a version of them – you’ll encounter no shortage of grand predictions.

“By 2020, 30% of web browsing sessions will be done without a screen.” Or, “By 2020, 50% of all searches will be conducted via voice.” (I’ll come back to that one in a second). Or, “2017 will be the year of voice search.” Oops, looks like we might have missed the boat on that last one.

The great thing about the future is that no-one can know exactly what’s going to happen, but you can have fun throwing out wild predictions, which most people will have forgotten about by the time we actually get there.

That’s why you get so many sweeping, ambitious, and often contradictory forecasts doing the rounds – especially with a sexy, futuristic technology like voice. It doesn’t do anyone any real harm, unless for some reason your company has decided to stake its entire marketing budget on optimising for the 50% of the populace who are predicted to be using voice search by 2020.

However, in this state of voice search series, I’ve set out to take a realistic look at voice search, beyond the hype, to determine what opportunities it really presents for marketers. But when it comes to predicting the future, things get a little murkier.

I've made some cautious predictions to the tune of assuming that if smart speaker ownership increases over the coming years, voice search volume will also likely increase; or that mobile voice search might be dropping away as smart speaker voice search catches on.

In this article, though, I'll be looking at where voice search as a whole could be going: not just on mobile, or on smart speakers, but of any kind. What is the likelihood that voice search will go "mainstream" to the point that it makes up as substantial a portion of overall search volume as is predicted? What are the obstacles to that? And what does this mean for the future of voice optimisation?