Talking and texting may have been the first things we used mobile devices for, but they’re hardly the only ones anymore. And when it’s just as easy to place a video call via Skype, send an instant message through WhatsApp, tweet, or check in on Facebook, summoning a phone’s dialer tends to be an afterthought. So could we could be approaching a time when it makes little sense to even have a voice or text plan?

To get a sense of how feasible it might be to do without one, I spent the recent holiday week in December trying to abstain from using the voice and SMS services on my Android device (or my landline phone at the office).

There are good reasons to think that a data plan may be all you need. People are indeed spending less time on wireless calls—only 1.8 minutes per call in 2011, down from 3.1 minutes in 2007—and according to PricewaterhouseCoopers, the number of minutes is declining overall. Juniper Research predicts that one billion people will use voice and video calling through apps on mobile devices by 2017, about the same number that use smartphones today. Simultaneously, 4G mobile networks are expanding and getting more reliable, Wi-Fi is available in more places, and a growing number of companies are offering very good free or low-priced voice, video chat, and messaging apps that run over these data networks. Even Facebook is introducing free calling to its mobile Messenger app, starting with iPhone users in Canada; some carriers are also getting involved.

Somewhat surprisingly, I could not last a whole week without voice. But it was a fascinating experiment, and I quickly realized that thanks to the new possibilities opened up by some clever apps,one-on-one data communication is gradually becoming more interesting.

As an Android device owner, I used two mobile apps to make outgoing calls to any landline or mobile device: Skype, which is owned by Microsoft, and Rebtel, from a Swedish company that claims to be the second-largest mobile voice-over-IP service, with 20 million users globally. With either app, people could see my regular phone number when I dialed, and I set up call forwarding so that I could use Skype to answer all incoming calls to my normal Verizon account.

The quality of mobile voice-over-IP is clearly improving, but it is not quite ready to replace traditional calling at a large scale. When calls went well, the voice quality actually seemed better than usual, and people on the other end often agreed. That will no doubt become a trend as carriers focus infrastructure investments on 4G networks—often at the expense of voice networks—and as app providers improve their own services. For example, a Skype spokesman told me that the company is now working to integrate Opus, a newly standardized audio compression algorithm, to provide CD-quality sound in its desktop and mobile software.

It was nice, too, that the apps replicated my usual dialing experience, integrating with all my phone contacts. And neither Skype nor Rebtel consumed unreasonable amounts of data (about 30 to 40 megabytes each in a week), even though I had them open most of the time (I did not use much video).

But some calls didn’t go well at all, especially if I was trying to reach people on their phones, not through Skype or Rebtel accounts. Several calls were dropped or plagued by distracting audio delays, probably because of a poor data connection or a network that switched from 4G to 3G service. Rebtel was generally more reliable, and it offers the option of switching to its local calling service over the cellular network in mid-call if data or Wi-Fi service begins getting patchy. But I cheated a number of times when I had to make important, quick, or time-sensitive phone calls and just used my device’s dialer.

My attempt to avoid texting was more difficult, partly because I text a lot. Most messaging apps generally require the recipient to be signed up for the service as well. I barely found any of my usual contacts through the popular WhatsApp service, and only a few were on Skype. I was slightly more successful with Google Talk. Facebook Messenger came the closest to being an SMS replacement, since many of my friends were set up to receive mobile chats, and now the company doesn’t even require a Facebook account to sign up.

The experiment was hypothetical, of course, and few smartphone owners seem ready to let go of their voice plans. In fact, some new smartphone contracts don’t provide the option of reducing voice minutes to save money, let alone giving up voice service altogether. The two dominant wireless carriers, Verizon and AT&T, now bundle unlimited minutes and texting with tiered data service plans for smartphones (though not tablets). This allows the carriers to hang on to relatively lucrative revenue streams from lower-bandwidth voice networks for as long as possible, even while charging more for data use. It also lowers the incentive to adopt mobile talking and chatting apps.

But even without a financial incentive, the features that come with communicating over data networks are compelling. Suddenly, rather than just talking with my ear to the handset, I could open up a face-to-face video call, reach out to a Facebook contact whose number I don’t have, send a friend my current location while talking, or forward a photo or message that self-destructs in a few seconds via the privacy-protecting app SnapChat.

There will be more innovations to come, whether network carriers like it or not—though they do have some power to slow the adoption of mobile VoIP services, says Susan Crawford, a former communications policy advisor to President Obama. For example, they could discourage video calling with burdensome data overage fees—or block such services outright, as AT&T tried to do with Apple’s Facetime video-chat app last year.

“Phone calls have been the same way for 100 years,” says Tim Tuttle, founder of Expect Labs in San Francisco. “Carriers have controlled the network, and there’s been no ability to build technologies on top of it.”

Tuttle’s startup is building a calling app, first for iPad, that will listen in on a conversation and, like Apple’s personal assistant Siri, recognize key terms to pull up information that is relevant to the ongoing discussion, such as movie times or a phone contact. The company also plans to sell a technology platform designed to help employees collaborate on documents while talking on their phones.

Rebtel CEO Andreas Bernstrom says he would like to see someone devise a way to make calls across different mobile voice-over-IP services so that a Rebtel user could, for example, call a Skype user. The company recently released a developer platform so that any app can use its calling technology.

I might be willing to forgo a voice plan one day. But the replacement features would have to be a little more reliable and compatible with one another, and there’d have to be some savings involved. I have faith that the first two things will happen, but as Crawford told me, the dominant network carriers will find ways to make sure talk doesn’t get too cheap.