Probably because of the united hate of the Roman Empire. The empire kind of created two cultures. The on inside it's borders, and the one outside it's borders. Even the Romans themselves would note that the "barbarians" had a similar culture between themselves. Still there were many rivalries among the groups that destroyed the Western Roman Empire, and surprisingly, they used mixed Roman culture with there's.
We cannot decipher their languages as easily as some may think. Over the past 3000 years, the human race has gone through probably a few thousand languages, but even if it was the same language all the way back to ancient times, the meanings of words & symbols change frequently.
Take the Swastika for example. This is an extreme change, but today in America, if you flaunt a Swastika, you're a racist.
150 years ago, the Swastika was a sign of good luck & prosperity to many religions.
Answer: The contribution made by the Soviets was vital. They provided diplomatic support, strategic and grand tactical planning, including the planning of the invasion of South Korea, and essential logistical support. They supplied and trained the air forces of China and North Korea
As government spending increased, America came out of the Great Depression and moved toward higher productivity.