Do you talk to machines? And more importantly, do they talk back to you? If you find yourself talking to appliances, you're not going crazy. You're probably like me and the billions of others who have developed relationships with our phones, TVs, and speakers to play music, locate an address, or send a text. Voice assistants have gone from application to ubiquity.

Nobody knows this better than the man who helped first bring digital voice assistants (sometimes called virtual assistants) to the market on a large scale--Dag Kittlaus, the co-founder of Siri. Kittlaus and co-founder Adam Cheyer created the virtual assistant company Siri in 2007. No sooner had they launched Siri as an application on the Apple Store in 2010 than Steve Jobs purchased their company. With the launch of the iPhone 4S in 2011, the world started talking at their phones instead of using their phones to talk to people.

Since selling Siri to Apple, Kittlaus has been busy. He and Cheyer started a new digital voice company Viv (which is called Bixby on Samsung devices) and Kittlaus has become a thought leader in virtual assistant technology. On one of my recent visits to Silicon Valley, he took time from his busy schedule to chat with me about the future of voice technology.

Here is what Kittlaus sees as some of the promises and challenges of voice. 

Voice will be on more devices.

Voice isn't a fad. It's not just for people who want their hands free. Voice will be essential because we can talk faster than we can type.

Voice assistants are going to show up everywhere in your life--car, work, home, hotels, and restaurants. You might be talking to your washing machine at the laundromat or the vending machine in the lobby. And they'll be talking back, offering advice or suggestions.

Kittlaus says his new version of Bixby will soon be on more than 1 billion Samsung enabled devices. Count in the billions of devices supported by Apple, Amazon, and Google, and we'll be surrounded by talking machines.

Voice will be more useful.

Until now, people haven't used voice devices very much because the tasks they can do have been very narrow. For example, most people use voice assistants--like I do--to find an address, start a call, dictate a text, or set an alarm. We can't have conversations with them--yet.

But Kittlaus sees companies like Alexa and his own company, Viv, leading the way with more helpful skills, especially with third-party devices. In the near future, you'll be able to interact with more phone apps as well as more devices in your home, work, and in the world. With machine learning, there will be personalization, habits, and preferences that will make the devices even more useful.

In the future, you could order pizza through your Dominoes app, make a move with your chess playing app, or tune your guitar with your tuning app--all with your voice. All without touching your phone. And probably with the device anticipating what you want, based on your habits.

Voice will have to overcome privacy concerns.

But there are still some hurdles to overcome before voice assistants are adopted all over. One primary concern is privacy--because the device listens to our voice. 

Kittlaus points out the device only becomes active when it hears the "wake word," such as "Hey Siri,"  "Hey Google," or "Alexa." The devices aren't recording our conversations.

The virtual assistant companies take privacy seriously. That said, Kittlaus recognizes the real danger to privacy is not from the makers of virtual assistants but rather from hackers who could break into our devices and use them to spy on us. And if you are afraid of that, he says, don't buy voice assistant devices.

Voice assistants aren't perfect yet, and they have privacy issues to overcome, but they're getting better every day. Someday in the near future, you'll look at someone at work typing on their phone or computer keyboard and wonder why they are doing things the slow, old-fashioned way.