ELSA Speak is described as 'ELSA is a virtual pronunciation coach, a mobile application to help everyone speak English like a native speaker. ELSA is an artificial intelligence teacher who will help you have perfect English pronunciation, practice frequently-used English words, phrases and communications' and is an app in the education & reference category. There are more than 25 alternatives to ELSA Speak for a variety of platforms, including Web-based, iPhone, Android, iPad and Android Tablet apps. The best ELSA Speak alternative is YouSpeak, which is free. Other great apps like ELSA Speak are Saynest Lab, Artikulate, BandCheck and InterviewAI.
Open source, free for 5h/month then 0.8$/hour. The code is already done. It's just perfect!