I watched a video and decided to note down the most interesting things with screenshots.
In school, and some in university, we are told about the Proto-Indo-Europeans, who lived very long ago, and from whom many modern languages derived: English, Russian, Italian and even Hindi. All this happened due to the constant migration, wars and most importantly, the absence of a written language. People did not have written language standards, so they could easily be replaced.
Indo-European languages can be divided into two main groups: centum and satem, depending on how they pronounce the word "hundred": with "k" sound (lat. centum, gr. ἑkατόν) or "s/š" (rus. сто, lit. šimtas).
Since there was no written language back then, scholars reconstruct the Proto-Indo-European language using the comparative method, by finding correspondences between various languages. For example, they took the word "ten" from different languages, collected the most popular letters and sounds, and obtained *déḱm̥. The asterisk indicates that the word does not exist in any written sources, and this is just its reconstructed representation.
There's even a fable in the Proto-Indo-European language:
Examples of related words:
Interestingly, it's not just word roots that can be related. For example, the English suffix -ish is related to the Russian suffix/endings -ский:
You might think after this that we are all related, but no, linguistic relatedness does not imply a genetic relation between the speakers of these languages.
And it's a whole different story with Turkic and Finno-Ugric languages because they belong to completely different language families.