Duolingo (NASDAQ: DUOL) delivered a strong set of results in its latest earnings report. Revenue grew about 35% year over year to roughly $283 million in the fourth quarter, while the company surpassed $1 billion in annual bookings for the first time. Profitability remained solid, with adjusted EBITDA margins near 30%. By most operating metrics, the business continues to execute well. Yet the stock fell. That disconnect comes down to one thing: A change in investors' expectations. Let's see why. Will AI c ...