X0508 4 2025-11-17 0 0001562088 Duolingo, Inc. DUOL 0001870350 Glance Natalie C/O DUOLINGO, INC. 5900 PENN AVENUE PITTSBURGH PA 15206 0 1 0 0 Chief Engineering Officer 1 Class A Common Stock 2025-11-17 4 S 0 2534 177.95 D 113637 D Class A Common Stock 2025-11-18 4 S 0 160 173.7975 D 113477 D Class A Common Stock 2025-11-18 4 S 0 741 174.9689 D 112736 D Class A Common Stock 2025-11-18 4 S 0 850 175.7316 D 111886 D Class A Common Stock 2025-11-18 4 S 0 560 176.9964 D 111326 D Class A Common Stock 2025-11-18 4 S 0 160 177.6025 D 111166 D Class A Common Stock 130 I By son Represents shares automatically sold to satisfy tax withholding obligations in connection with the vesting of Restricted Stock Units ("RSUs") and delivery of shares. The sale was effected pursuant to the Reporting Person's Rule 10b5-1 trading plan adopted on November 14, 2024. 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 $173.36 to $174.21, 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 $174.39 to $175.38, 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 $175.40 to $176.35, 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 $176.45 to $177.33, 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 $177.51 to $177.74, 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. /s/ Stephen Chen, as Attorney-in-Fact for Natalie Glance 2025-11-19