The number of teens who voice call on their phones every day dropped 50% between 2009 and 2012. Just 3% of UK Millennials now use the function daily. With texts, iMessage and WhatsApp becoming the preferred method of communication, can audio message app Cord get us talking again?

In Spike Jonze's Her, protagonist Theodore Twombly converses with his operating system as though she was a real human. And while Her is set in the future, voice user interface is increasingly relevant to the streamlined design modern consumers have grown accustomed to.

From messaging to social media to a marketplace to browsing the internet, WeChat is the app the does everything. While Western companies and app developers race to unbundle their services into efficient single-purpose apps, WeChat continues to add feature after feature.

The Apple App Store houses over one million apps. Despite once trying to do everything, apps are now being split into single purpose platforms. But how do people actually use them? And which is more useful – the Swiss Army knife approach or a tailored, single purpose app?