According to Yahoo Finance, with the raise, Duolingo accepted its first outside investor in almost three years. General Atlantic will take a board observer seat at the company, per Duolingo.

The company, which was last valued at $1.5 billion, says the round has increased its valuation, but it declined to share by how much.

General Atlantic has invested in a number of edtech companies around the world, like OpenClassrooms, Ruangguru and Unacademy. Duolingo said that General Atlantic's global platform and experience with online education in Asia would help guide its own growth, specifically pointing to its plans to scale up the Duolingo English test.

The e-learning company last raised $30 million in December at that $1.5 billion valuation. To raise a smaller sum a few months later is uncommon. Historically, that type of raise could happen for a number of reasons: a company is accepting a later investment as part of the same funding round, it needs more cash and this is an easy way to raise it or the company tried to raise a new large round and failed to secure past $10 million.

So where does the language learning unicorn fit?

In Duolingo's case, it said the $10 million was raised because it wanted to bring a new investor on, but didn't need a massive amount of primary capital. Duolingo says it is cash-flow positive.

In the past few weeks, Duolingo launched a new app to help children read and write, passed one million paying subscribers for Duolingo Plus and disclosed that its annual bookings run rate is $140 million. The company also recently hired its first CFO and general counsel.

"Because our business has been growing very fast and we have more than enough capital, there was limited need for us to raise more primary capital. However, over the last year, we developed a relationship with General Atlantic," the company said in a statement to TechCrunch.

Tanzeen Syed, a managing director for General Atlantic, said that Duolingo is a "market leader in the language learning space. Syed also said Duolingo has a "profitable, efficient business model while maintaining hyper-growth characteristics."

Another key factoid here is that along with the $10 million, there was a larger secondary transaction, which occurs when an existing stockholder sells their stock for cash or to a third party, or to the company itself while the company is still private.

In this case, an existing investor in Duolingo sold a small portion of their existing stake to allow General Atlantic to have a bigger stake in the company.

The company declined to share the size of the secondary market transaction.

In light of this new information, Duolingo's expansion to Asia, which has a robust market of English learners, welcomed one investor and lessened the stake of another.

Based on what we know, the transaction signals that a preexisting investor in Duolingo was looking for liquidity at a time where the public markets are tightening and private markets are pausing. And at a time when companies are staying private longer than ever before, secondary transactions are hardly rare.

Sometimes, however, secondary transactions signal a lack of faith from a preexisting investor in the company's current trajectory.

Duolingo is full steam ahead on its goal to expand across the world -- and now has new cash in the bank, and a new observer seat on the board, to prove it.