How many words?

Could it be possible
that every rhyme has been rhymed,
every combination of words written
and we are simply copying another
but at a different moment in time?
Could it be possible
that nothing is new
or has the change in our grammar
evolved us ever so slightly,
we create something different,
but the idea is renewed.
7 billion some odd people
so many words to say
quick get me a mathematician
how many combinations does that make?