With mobile phones being used for more and more tasks these days, one thing is starting to fall by the wayside: talking. Between all that texting, tweeting, emailing, friending, Web browsing, picture taking and game playing, who’s got time to call anyone?

December marked the first time that data traffic on global mobile networks exceeded voice traffic, according to Swedish mobile technology company Ericsson. Mobile data traffic has risen 280% per year over the last two years, Ericsson says, and is forecast to double annually over the next five years.

Behind this stunning increase in the amount of data flying through the air are the ever-more-sophisticated smartphones (and now tablets such as the iPad); mobile users hooked on texting and social networking via Twitter and Facebook; and, of course, people working wirelessly on their laptops over mobile networks.

As it turns out, the bulk of the data being sent over mobile networks comes from the 400 million or so mobile broadband subscribers around the world, who now generate more data traffic than the voice traffic that comes from the 4.6 billion mobile phone users worldwide, Ericsson says. As an aside, those 4.6 billion mobile subscribers represent two thirds of the world’s population, who have adopted the new technology in little more than a decade. Many of those people have never had a landline phone.

On top of wanting to send and retrieve increasing amounts of data wirelessly, mobile users also want to send and receive it instantly without having to sing the “Jeopardy” song to themselves while they wait. That has the fiercely competitive wireless companies already planning their move to the next, and fourth, generation of mobile technology. Called 4G, naturally, the new technology promises speeds more than 10 times faster than the 3G networks still being touted across the country.

With speeds roughly comparable to wired broadband Internet, 4G networks should be plenty fast enough to make video calls, to watch the “Simpsons” on Hulu, or to get the kids into mobile multi-player games. They may even convince some people to cut their cable and telephone cords altogether as growing numbers are doing.

Like anything having to do with technology, the fourth generation of mobile technology comes with its own acronym, LTE, for Long-Term Evolution. This is the latest step in the development from the second generation, digital technology GSM, or Global System for Mobile communications, which was adopted in most countries around the world, and the third generation, higher-speed, multimedia-capable UMTS, or Universal Mobile Telecommunications Service.

Verizon Wireless has been conducting LTE trials in Boston and Seattle and plans to roll out the service in up to 30 markets by year-end 2010, with coverage areas encompassing about 100 million people. The company says download speeds should range from five to 12 megabits per second (Mbps). AT&T, whose iPhone deal with Apple is the envy of every other mobile carrier, says it will be holding field trials of LTE technology this year with commercial rollout expected in 2011.

Sprint has been moving to 4G through a rival technology, known as Wimax, or Worldwide Interoperability for Microwave Access. Wimax is a high-speed wireless technology akin to WiFi but with a range measured in miles rather than feet.

Sprint, which already has 4G coverage areas encompassing more than 40 million people, expects to extend that to more than 120 million people by year’s end. The company announced this spring that it expected to launch its first 4G Wimax phone in June. The EVO 4G “phone” from HTC boasts features such as simultaneous voice and data, meaning you can talk and browse the Web at the same time. It also features video chats and the ability to turn the phone into a mobile hot spot for other devices.

For its part, Apple has had the tech world in a twitter about its plans to release a 4G iPhone this summer. Talk about the device made headlines when a prototype was left in a bar and found its way into the hands of a technology blogger who tore it down to bare all its features.

While the world hurtles toward the latest feature-packed mobile phone, which may be used to do everything but talk, spare a thought for those old landline desk phones now gathering dust across America. They might not take pictures, but they’ll definitely make the call.