Duolingo, Inc.

(a) None.

(b) Trading Plans

On May 27, 2025, Stephen Chen, General Counsel, entered into a 10b5-1 sales plan (the “Chen 10b5-1 Sales Plan”) intended to satisfy the affirmative defense of Rule 10b5-1(c) of the Exchange Act and providing for (i) the sale of the net number of shares of Class A common stock underlying 11,187 unvested restricted stock units received after giving effect to the number of shares automatically sold to satisfy tax withholding obligations on each applicable vesting date (such total number of shares covered under clause (i) is not determinable) and (ii) the sale of 10,996 shares of Class A common stock. The Chen 10b5-1 Sales Plan will remain in effect until the earlier of (1)August 14, 2026, (2) the date on which all trades set forth in the Chen 10b5-1 Sales Plan have been executed, or (3) such time as the Chen 10b5-1 Sales Plan is otherwise terminated according to its terms.

On May 27, 2025, Gillian Munson, amember of our Board of Directors, entered into a 10b5-1 sales plan (the “Munson 10b5-1 Sales Plan”) intended to satisfy the affirmative defense of Rule 10b5-1(c) of the Exchange Act and providing for the potential exercise of vested stock options and the associated sale of up to 3,062 shares of the Company’s Class A common stock. The Munson 10b5-1 Sales Plan will remain in effect until the earlier of (1)February 27, 2026, (2) the date on which all trades set forth in the Munson 10b5-1 Sales Plan have been executed, or (3) such time as the Munson 10b5-1 Sales Plan is otherwise terminated according to its terms.

On May 27, 2025, Matthew Skaruppa, Chief Financial Officer, entered into a 10b5-1 sales plan (the “Skaruppa 10b5-1 Sales Plan”) intended to satisfy the affirmative defense of Rule 10b5-1(c) of the

Exchange Act and providing for (i) the sale of the net number of shares of Class A common stock underlying 23,429 unvested restricted stock units received after giving effect to the number of shares automatically sold to satisfy tax withholding obligations on each applicable vesting date (such total number of shares covered under clause (i) is not determinable), (ii) the sale of 6,500 shares of Class A common stock and (iii) exercise of vested stock options and the associated sale of up to 1,378 shares of the Company’s Class A common stock. The Skaruppa 10b5-1 Sales Plan will remain in effect until the earlier of (1)August 14, 2026, (2) the date on which all trades set forth in the Skaruppa 10b5-1 Sales Plan have been executed, or (3) such time as the Skaruppa 10b5-1 Sales Plan is otherwise terminated according to its terms.

On June 9, 2025, Robert Meese, Chief Business Officer, entered into a 10b5-1 sales plan (the “Meese 10b5-1 Sales Plan”) intended to satisfy the affirmative defense of Rule 10b5-1(c) of the Exchange Act and providing for (i) the sale of the net number of shares of Class A common stock underlying 3,151 unvested restricted stock units received after giving effect to the number of shares automatically sold to satisfy tax withholding obligations on each applicable vesting date (such total number of shares covered under clause (i) is not determinable) and (ii) the sale of 18,296 shares of Class A common stock. The Meese 10b5-1 Sales Plan will remain in effect until the earlier of (1)May 29, 2026, (2) the date on which all trades set forth in the Meese 10b5-1 Sales Plan have been executed, or (3) such time as the Meese 10b5-1 Sales Plan is otherwise terminated according to its terms.

On June 11, 2025, Dr. Luis von Ahn, Chief Executive Officer and member of the Company’s Board of Directors, and the Luis von Ahn Foundation, entered into a 10b5-1 sales plan (the “von Ahn 10b5-1 Sales Plan”) intended to satisfy the affirmative defense of Rule 10b5-1(c) under the Exchange Act, pursuant to which a maximum aggregate of up to 431,000 shares of the Company’s Class A common stock may be sold, consisting of (i) up to 226,000 shares issuable upon the exercise of vested stock options held by Dr. von Ahn, (ii) up to 200,000 shares held by Dr. von Ahn, and (iii) up to 5,000 shares held by the Luis von Ahn Foundation). The von Ahn 10b5-1 Sales Plan will remain in effect until the earlier of (1)September 15, 2026, (2) the date on which all trades set forth in the von Ahn 10b5-1 Sales Plan have been executed, or (3) such time as the von Ahn 10b5-1 Sales Plan is otherwise terminated or expires according to its terms.

On June 13, 2025, William Gordon, amember of our Board of Directors, entered into a 10b5-1 sales plan (the “Gordon 10b5-1 Sales Plan”) intended to satisfy the affirmative defense of Rule 10b5-1(c) of the Exchange Act and providing (i) the exercise of vested stock options and the associated sale of up to 10,000 shares of the Company’s Class A common stock, and (ii) the sale of 30,000 shares of Class A common stock. The Gordon 10b5-1 Sales Plan will remain in effect until the earlier of (1)September 30, 2026, (2) the date on which all trades set forth in the Gordon 10b5-1 Sales Plan have been executed, or (3) such time as the Gordon 10b5-1 Sales Plan is otherwise terminated according to its terms.

No other “officer” (as defined in Rule 16a-1(f) under the Exchange Act) or director of the Company adopted, modified orterminated “Rule 10b5-1 trading arrangements” and/or “non-Rule 10b5-1 trading arrangements” (each as defined in Item 408 of Regulation S-K) during the three months ended June 30, 2025.