X0609 4 2026-09-21 0 0001562088 Duolingo, Inc. DUOL 0001829259 von Ahn Luis false C/O DUOLINGO, INC. 5900 PENN AVENUE PITTSBURGH PA 15206 1 1 1 0 President & CEO, Co-Founder 1 Class A Common Stock 2026-09-21 4 C 0 27960 14.42 A 27960 D Class A Common Stock 2026-09-21 4 C 0 9406 38.08 A 37366 D Class A Common Stock 2026-09-21 4 S 0 33257 150.4641 D 4109 D Class A Common Stock 2026-09-21 4 S 0 4109 151.0699 D 0 D Class A Common Stock 2026-09-22 4 C 0 3614 38.08 A 3614 D Class A Common Stock 2026-09-22 4 S 0 200 150 D 3414 D Class A Common Stock 2026-09-22 4 S 0 3414 152.02 D 0 D Stock Option (Right to Buy) 14.42 2026-09-21 4 M 0 27960 0 D 2029-12-12 Class B Common Stock 27960 0 D Class B Common Stock 2026-09-21 4 C 0 27960 0 A Class A Common Stock 27960 3396080 D Class B Common Stock 2026-09-21 4 C 0 27960 0 D Class A Common Stock 27960 3368120 D Stock Option (Right to Buy) 38.08 2026-09-21 4 M 0 9406 0 D 2030-12-02 Class B Common Stock 9406 160342 D Class B Common Stock 2026-09-21 4 C 0 9406 0 A Class A Common Stock 9406 3377526 D Class B Common Stock 2026-09-21 4 C 0 9406 0 D Class A Common Stock 9406 3368120 D Stock Option (Right to Buy) 38.08 2026-09-22 4 M 0 3614 0 D 2030-12-02 Class B Common Stock 3614 156728 D Class B Common Stock 2026-09-22 4 C 0 3614 0 A Class A Common Stock 3614 3371734 D Class B Common Stock 2026-09-22 4 C 0 3614 0 D Class A Common Stock 3614 3368120 D The sale was effected pursuant to the Reporting Person's Rule 10b5-1 trading plan adopted on June 2, 2026. The price reported in Column 4 is a weighted average sale price calculated by the broker executing the sales. These shares were sold in multiple transactions at prices ranging from $150.00 to $150.99, inclusive. The Reporting Person hereby undertakes to provide to the Securities and Exchange Commission staff, the Issuer, or a security holder of the Issuer, upon request, full information regarding the number of shares sold at each respective price within the range set forth in this footnote. The price reported in Column 4 is a weighted average sale price calculated by the broker executing the sales. These shares were sold in multiple transactions at prices ranging from $151.00 to $151.36, inclusive. The Reporting Person hereby undertakes to provide to the Securities and Exchange Commission staff, the Issuer, or a security holder of the Issuer, upon request, full information regarding the number of shares sold at each respective price within the range set forth in this footnote. The options are fully vested and exercisable. 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. /s/ Stephen Chen, as Attorney-in-Fact for Luis von Ahn 2026-09-23