Simplify the following text for a Grade 8 native English-speaking person.
Original: Mainstream scholarship places them in the general region of the Pontic-Caspian steppe in Eastern Europe and Central Asia , Some scholars would extend the time depth of PIE or Pre-PIE to the Neolithic or even the last glacial maximum , and suggest alternative location hypotheses .
Simplified: Mainstream scholarship places them in the general region of the steppes in Eastern Europe and Central Asia . Some scholars would extend the time of PIE much further back .