Duolingo (DUOL) shares fell 5.5% in premarket trading on Wednesday, February 11, 2026. The decline followed an announcement from T-Mobile (TMUS) regarding the launch of a real-time AI translation service.
The new T-Mobile feature enables live translation of phone calls across more than 50 languages. T-Mobile integrated the service directly into its wireless network infrastructure as a core feature.
Investors view the move as a direct competitive threat to Duolingo’s position in the language translation market. This perception triggered the negative reaction in the DUOL stock price.