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 not the standard Scratch 3.
My idea is to can I set it to react one way when I say "hello"; then say "french" and then say "hello" it says "Bonjour". Two other extensions are needed along with the Speech to Text one - one for speech to text and the translate shown below.
Ok, so to the fun bit. The listen and wait, and when I hear blocks are the key new blocks, and they do what they say. The three sets of the code are ones I used for this activity.
Thank you to Machine Learning for Kids for creating such a brilliant Scratch extension - this is well worth a play with.