In his excellent natural history of language, The Power of Babel, linguist John McWhorter describes dialects – and it’s all dialects – as “developed far beyond the call of duty”. He’s referring to the way languages tend to become structurally and idiosyncratically baroque:
Left to its own devices, a human language will tend to elaborate into overt expression of subdivisions of semantic space that would not even occur to many humans as requiring attention in speech and become riddled with exceptions and rules of thumb and things only learnable by rote. This process tends to achieve its most extreme expression among groups long isolated, but any language that has been spoken for tens of thousands of years exhibits some considerable degree of “developmental overkill.” It is this feature of human language that contributes to why learning other languages as an adult is such a challenge. No language has been goodly enough to remain completely tidy and predictable, no language has not stuck its nose somewhere where it didn’t really need to go, no language classifies objects and concepts according to principles so universally intuitive that any human could pick them up in an afternoon, and in none of them are there classifications indexed to currently perceptible cultural concepts in anything better than a highly approximate manner.
This tendency towards complex over-elaboration manifests inevitably in any language that has been around long enough. The converse is that new languages have relatively little such ornamentation, which emerges only through centuries or millennia of “sound erosions and changes, grammaticalizations, rebracketings, and semantic change”.
Pidgins are simplified languages, largely stripped of unnecessary complication, that arise for utilitarian reasons between groups who lack a common tongue. So when these are “born again” as full-fledged languages, in the form of creoles, the results are comparatively free of overdevelopment – before the engine of encrustation gets going again for subsequent generations.