In the tech world, innovation and investment are almost always tied at the hip. Venture capitalists find a brilliant idea and support it with piles of cash, helping bring it into your home, your office or onto your mobile device.

In short, VC firms rarely ever ignore the next big thing. Looking back at the short history of voice applications, however, they might have missed a huge trend.

Gustaf Alströmer, VP of growth at Voxer, told Business Insider earlier today that the VC community completely whiffed on voice last year and are now stuck watching more voice-enabled applications climb up the charts each day.

"If you look back two years ago, there weren't any voice apps," Alströmer told Business Insider. "Apple wasn't sure if they were going to allow VoIP applications at all. Everyone was talking about if Skype (News - Alert) would be allowed...and now it's one of the top apps."

Even without significant VC backing, eight voice apps have found their way onto the list of the top 25 social networking applications, according to Business Insider. Included on the list are Skype and Voxer – which turns any smartphone into a walkie talkie – and a host of apps that enable free voice and video calling: Tango Video Calls, Viber and ooVoo (News - Alert) Video Chat to name a few.

With the success of these apps, developers have begun integrating voice functionality into previously-established mobile applications. Just last month, Twilio (News - Alert) released its native software development kit for iOS, giving iPhone (News - Alert), iPad and iPod Touch developers the ability to load a fully functioning VoIP phone into any mobile app.

Expect to see voice added into mobile games, travel apps, CRM software and other application genres in the near future. The only question for developers that use voice as a supplementary feature is if they should eat the cost themselves or pass it along to the user. And if so, how?