The claim that the language learning app Duolingo has been banned from TikTok is just not true. Duolingo currently has an up-and-running account on TikTok, which has a video uploaded and many products for sale on TikTok's online shop. After reviewing the video from TikTok and the account on TikTok, as well as the video, it seems that the app had some sort of rebirth as an app. AI features are improving, and as seen in the intriguing video they have uploaded, they seem to be creating a new identity, different from their other one, which might be connected to the account's brief blank profile on TikTok. There isn't much information about if Duolingo was banned, but most of what I've briefly read is no. I couldn't find a reliable source that directly answers the claim. Below is the link to the page Duolingo has on TikTok.