UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Duolingo, Inc. (Exact name of registrant as specified in its charter) FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2021 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission file number 001-40653 Delaware 45-3055872 (State or other jurisdiction of incorporation or organization) (I.R ...