X0609 4 2026-08-17 0 0001562088 Duolingo, Inc. DUOL 0001870350 Glance Natalie false C/O DUOLINGO, INC. 5900 PENN AVENUE PITTSBURGH PA 15206 0 1 0 0 Chief Engineering Officer 1 Class A Common Stock 2026-08-17 4 S 0 2751 129.13 D 170650 D Class A Common Stock 2026-08-18 4 S 0 502 137.0094 D 170148 D Class A Common Stock 2026-08-18 4 S 0 1037 138.187 D 169111 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 and delivery of shares. The sale was effected pursuant to the Reporting Person's Rule 10b5-1 trading plan adopted on September 15, 2025. 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 $136.68 to $137.61, 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 $137.72 to $138.59, 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 2026-08-19