Momkin Android App
Momkin (from Arabic ممكن, "doable") helps you learn languages by visualizing what's being said. All you need is some audio file that goes with a subtitle file (supported format: .srt). You can download those files with apps like NewPipe, but you can also create them yourself with programs like Aegisub. In the future, it's planed for Momkin to explicitly support the Birkenbihl approach (German Wikipedia entry) by allowing word-to-word translations of the original transcript.
This program is Free Software: You can use, study share and improve it at your will. Specifically you can redistribute and/or modify it under the terms of the GNU Affero General Public License as published by the Free Software Foundation, version 3 of the License.