The Raspberry Pi Foundation recently released a programming activity Alien Language , with support Dale from Machine Learning for Kids , that is a brilliant use of Scratch 3 - Speech Recognition to control a sprite in an alien language. Do the activity, and it is very much worth doing, and it will make sense! I would also recommend going to the machinelearningforkids.co.uk site anyway it is full of exciting things to do (for example loads of activities https://machinelearningforkids.co.uk/#!/worksheets ) . Scratch 3 has lots of extensions that are accessible through the Extension button in the Scratch 3 editor (see below) which add new fun new blocks to play with. The critical thing for this post is Machine Learning for Kids have created a Scratch 3 template with their own extensions for Scratch 3 within it https://machinelearningforkids.co.uk/scratch3/ . One of which is a Speech to Text extension (see below). You must use this one ...
Robots and getting computers to work with the physical world is fun; this blog looks at my own personal experimenting and building in this area.