Answer: were herders from the steppes of today's Russia and Kazakhstan.
Step-by-step explanation:
There exists a theory that states that the Kurgan people were the origin of the Proto-Indo-European group of languages. These people were simply nomadic herders who came from the steppes of what is now Russia and Kazakhstan.
Upon getting to Europe and South Asia, they conquered much of the land and infused their language into local languages when they took over thereby leading to the formation of various but similar languages that we today call the Indo-European group of languages.