Ural-Altaic languages are a group of languages that are similar to each other in some ways. Think of it like a group of friends who are all really good at soccer - they all have some similarities in the way they play the game, but each person has their own unique style too.
The Ural-Altaic language group includes languages like Turkish, Mongolian, Finnish, and Hungarian. These languages all have some things in common, like the way they build words using prefixes and suffixes, and the way they use vowel harmony (which means that certain vowels only fit together in specific ways).
Some people think that all of these languages come from a common ancestor - kind of like how you and your cousins might all come from the same grandparents. But not everyone agrees on this, and some people think that the similarities between these languages are just a coincidence.
Either way, languages in the Ural-Altaic group are interesting to study because they show us how different languages can have some things in common, even if they're spoken in different parts of the world.