In an early morning phone call on Tuesday, an Apple executive congratulated Duolingo founder Luis Von Ahn on the Oakland company's designation as 2013 App of the Year -- and warned him to secure company servers for a new onslaught of business.

Not long after, Apple announced publicly that the language learning software app was the editor's choice for the iTunes App Store 2013 App of the Year.

The free iPhone app, described in the computer giant's app store as "fantastically well-designed and easy to use," beat out San Francisco-based photo editing app VSCO Cam and San Francisco-based educational game Endless Alphabet.

Mr. Von Ahn, a professor of computer science at Carnegie Mellon University, reported a definite increase in activity following the announcement.

But despite the push from Apple, an influx of new users isn't exactly new to the company this year.

Duolingo has seen its user base soar from 3 million in May to 16 million in December.

He said the designation from Apple was particularly notable because it made Duolingo the first education app to take home App of the Year and also the first non-Silicon Valley based company to take home the prize.

The nod from Apple is icing on the cake for Duolingo, which has also been named iPhone App of the Year in more than a dozen countries.

In September, the company also announced partnerships with New York-based Buzzfeed and Atlanta-based CNN.com that will allow Duolingo users to learn languages by translating content from the media companies' websites into new languages.

Mr. Von Ahn said his company won't be resting on its laurels. Next year's to-do list includes adding 44 new languages that will be taught through the app.

First Published: December 17, 2013, 6:41 p.m.