Fluent — Language Learning App

We have developed Fluent, a cross-platform e-learning application that allows users to study languages through literature. At the heart of Fluent is a custom Epub reader designed to enhance language learning. This reader supports both dark and light themes and offers adjustable font sizes and audio playback speeds. Users can translate words and sentences directly within the app while reading or listening, with the option to hear pronunciation and add new vocabulary to a personalized list. The app’s extensive library hosts a wide range of books, and users also have the flexibility to upload their own.

One of the standout features of this reader is its optimization for weaker devices, ensuring smooth performance across both small and large texts. This is achieved through our own implementation using customized Flutter packages.

Innovatively, Fluent introduces a unique registration system that bypasses the need for email or phone number by utilizing Device ID and cryptography. This ensures that users’ progress is saved and can be restored even if the app is deleted, without traditional registration methods. User onboarding and application setup are conducted via an interactive chatbot.

The application includes a system of paid subscriptions and in-app purchases, managed through both the App Store and Play Store. This system incorporates server-side validation where a significant portion of the subscription logic is handled server-side.

Fluent also operates fully offline, caching necessary data and Epub files as well as storing the voiceovers for certain books, ensuring that users can access the full functionality of the app without an internet connection.

From a technological perspective, the most intriguing aspect of Fluent is the development of an Epub reader and parser for Flutter, supported by a server-side translator and text-to-speech reader hosted on Google Cloud, leveraging Google Translate API and Google Text-to-Speech.