Nearly two in five children have used a tablet or smartphone before they could speak in full sentences, according to a new report.

Conducted by family advocacy organization Common Sense Media, the study found that 38% of children under the age of 2 have used a mobile device for playing games, watching videos or other media-related purposes. In 2011, only 10% had.

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By the age of 8, 72% of children have used a smartphone, tablet or similar device.

"This is the true sign that the digital generation has arrived," Common Sense Media's founder and CEO Jim Steyer told Mashable.

The study found that mobile-device use among very young children is growing rapidly, especially compared to other mediums. Television viewership remained stable, with 66% of children under 2 watching in both 2011 and 2013. Computer use grew from 4% to 10% over the two years, but DVD viewership actually declined, from 52% in 2011 to 46% in 2013.

Not only are more children using tablets and smartphones, they're using them for longer periods of time. The amount of time spent using these devices tripled: In 2013, children ages 0 to 8 spent an average of 15 minutes a day using mobile devices; that's up from 5 minutes a day in 2011.

"We're seeing a fundamental change in the way kids consume media," Steyer said. "Kids that can't even talk will walk up to a TV screen and try to swipe it like an iPad or an iPhone."

Steyer explained that children's increased access to and use of mobile devices has its pros and cons. Tablets can be great educational tools, but if they're overused or serve as virtual babysitters, they may cause developmental harm, he said.

The American Academy of Pediatrics recommends that parents should bar all screen time, including mobile devices, for children under 2, but Steyer believes that's a conservative suggestion. When tablets and smartphones are used responsibly, and both time used and content is monitored, devices can serve many educational purposes.

"We need to make screen time learning time," he said. "Technology used wisely is an essential element to education."

Steyer emphasized that as mobile devices become even more heavily used by children, companies must strive to create "ethical and valuable," technology; that includes making devices and applications that do not encourage addiction, are educational and respect the privacy of families.

"This trend is a big deal to the tech industry, and there's a profound impact on children and families," he said. "We've got to use these things wisely."

Image: Flickr, Greg Tee