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.