X0508 4 2025-12-08 0 0001562088 Duolingo, Inc. DUOL 0001870272 Hacker Severin C/O DUOLINGO, INC. 5900 PENN AVENUE PITTSBURGH PA 15206 1 1 1 0 Chief Tech Officer, Co-Founder 0 Class A Common Stock 2025-12-08 4 C 0 50000 0 A 50072 D Class A Common Stock 2025-12-08 4 G 0 50000 0 D 72 D Class B Common Stock 2025-12-08 4 C 0 50000 0 D Class A Common Stock 50000 2836917 I See footnote Class B Common Stock Class A Common Stock 147787 147787 D Each share of Class B Common Stock is convertible at any time at the option of the Reporting Person into one share of Class A Common Stock and has no expiration date. Each share of Class B Common Stock will convert automatically into one share of Class A Common Stock in connection with: (i) any transfer, whether or not for value, except for certain permitted transfers further described in the Issuer's amended and restated certificate of incorporation, (ii) such time as the aggregate number of shares of Class B Common Stock outstanding ceases to represent 5% of the aggregate number of shares of Common Stock outstanding, and (iii) the death of the Reporting Person. Shares held by SBH Trust dated March 10, 2020, of which Reporting Person is Trustee. /s/ Stephen Chen, as Attorney-in-Fact for Severin Hacker 2025-12-09