> For instance, the broad Australian accent (also called "Ocker"), which is more common in rural areas than metropolitan areas, has a prominent nasal twang and an emphasis on drawn-out long vowels. These characteristics are favourable for carrying over long, open distances with few obstructions. Rural accents in the U.S. exhibit similar adaptations.

My understanding agrees with other commenters in the thread - that there's no demonstrated connection between linguistic features and environment, and that connections like those are just intuited explanations rather than demonstrated scientific conclusions. Do you have a source you can cite for these?

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