Hey kiddo, do you know what a substrate is? It's kind of like the foundation or the base of something. Now, let's talk about the Vasconic Substrate Hypothesis. It's a theory that suggests that a long time ago, before people even wrote things down, there was a language spoken in Europe called Vasconic. Some people believe that this language was spoken by early humans for thousands of years and had a big influence on the languages spoken in Europe today.
Think about it like this: imagine building a big tower of blocks. The bottom layer of blocks is like the Vasconic language - it's the foundation that everything else is built on. As people started speaking different languages and moving to different areas of Europe, they built on top of that foundation, kind of like adding layers to a tower of blocks. But, even though they added new layers, they couldn't completely get rid of that bottom layer.
So, even though we don't speak Vasconic anymore, the words and sounds from that language might still be there in the languages we speak today. Kind of like how you can still see the block at the bottom of the tower even though it is covered up by other blocks. It's a really interesting theory and a lot of people are still studying it to try to learn more about the history of language in Europe.