Here is a personal project I've been working on lately. It's not public, but just wanted to share. It's a custom chatbot I created using a LAMP stack. Its built on top of a framework called Program-O to handle the knowledgebase storage and processing along with some basic NLP. I added the web speech api functionality myself so it supports recognition as well as speech synthesis. Anyways, pretty proud of this one.

I am building a web application which is multimedia centric (mostly video chat). Text to Speech and vice versa.
I have chosen Node with mongoDb as backend API with React Frontend.
What stack would you suggest for such an application?