** Language learning platform Duolingo DUOL.O slides ~21.4% to $204.40 premarket

** Co forecast Q4 bookings below Street estimates as it looks to prioritise user growth, teaching quality on app

** J.P. Morgan cuts PT to $300 from $465; maintains "overweight"

** Cites slower Q3 Daily Active User (DAU) growth on reduced "unhinged" marketing content on English-speaking social media accounts

** Notes impressions rising due to recent ramp-up, but remain below peak levels; modest increase in marketing spend to support user trend

** Says co convinced AI will take it closer to human-level tutoring, and expects key investments in teaching efficacy, video calls, social features, math content and chess

** Stock rated "buy" on avg; median PT is $420.39, per data compiled by LSEG

** As of last close, DUOL falls ~19.4% this year

(Reporting by Akriti Shah in Bengaluru)

((akriti.shah@thomsonreuters.com))