What are some alternatives?
When comparing Langotto and Fluent, you can also consider the following products
Duolingo - Duolingo is a free language learning app for iOS, Windows and Android devices. The app makes learning a new language fun by breaking learning into small lessons where you can earn points and move up through the levels. Read more about Duolingo.
SimFlow - SimFlow is a powerful CFD software, focused on engineering and science.
MondlyAR - Learn languages in augmented reality
OpenFOAM - OpenFOAM® - Official home of The Open Source Computational Fluid Dynamics (CFD) Toolbox.