For every given language(with more than one word) A you can invent a new language B as good as A by simply swapping the definitions of words Eg English becomes E'nglish by swapping the word "dog" and "cat"
That does not matter... (or I don't see your point) German has words that have no English translation (Schadenfreude, Wanderlust) i still can create G'erman by swapping those two definitions or create G''erman by swapping the definition of Katze (cat) and Hund (dog)
There can be a Universal language but there will be different dialects and that is an arbitrary line to draw. Because in old English "world" looked like* In modern English it is worlds singular and worlds plural. So is that considered 2 languages or 1 with different dialects.
It is widely believed that around 3500 BC there was a single language spoken by the ancestors of all modern Indian and European populations, called the Proto-Indo-European language. This is the closest thing to a universal language that ever existed.