Let's Buy the... BROOKLYN BRIDGE.
There are two poles of thought about how language is acquired.
One (the Nativists) suggests it is an innate skill specific to our species (Lenneberg).
The other (the Behviorists) accounts for it in terms of learning theory (Skinner).
To cut to the quick, both are involved and... yet much more. Language does erupt and develop like a seed when it is given water. The water for language is speech (or signs) particularly when they occur as part of a social interaction.
It is difficult to forestall the growth of language under these conditions. But like a seed, the size of the ultimate plant is open to question.