They do not understand each other. Different languages, cultures, beliefs, not to mention the sexes, make communication difficult. They will have to overcome this disadvantage if they want to advance.
Yes, good observation.
Your comment reminds me of the curse god placed on humanity after the building of Tower of Babel:
Therefore is the name of it called Babel; because the LORD did there confound the language of all the earth: and from thence did the LORD scatter them abroad upon the face of all the earth.
There are good reasons mythology never leaves us; it hits at the core of our humanity.