This area of linguistics is a touchy subject. Really, how can we know the origins of language? With so many uncertainties when exploring phenomena from hundreds of thousands of years ago, the data could, it seems, go either way.
However, there is much evidence for the necessity of language. What do I mean when I say this? Simply, that language came about not by some whim or random evolutionary occurrence, but that language emerges when there is a need for communication. There are contemporary examples all around call 'pidgins.' A pidgin is the result of the need for communication within a group that shares no common language, and therefore creates a primitive 'language' by which to communicate. In the United States, for example, such 'pidgins' could form by way of English and Spanish.
Since language can be demonstrated as a necessity rather than an evolutionary fluke, the next question becomes : what made it a necessity? Without some form of culture, however primitive, humans would have no necessity for communication and therefore language.
From an evolutionary perspective, it also stands to reason that there was an existence of primitive culture before vocal language was a biological possibility. The need for communication leads to attempts at communication, and, therefore, evolutionary preference to what would allow that communication. The process, as gradual as the progression of a bird from flightless to flying, couldn't reasonably predate culture, but rather would be an evolutionary marker as the culture itself evolved.