I agree that they should be preserved, even celebrated.
Languages, and their unique regional dialects, are one of the most fundamental components of a group's identity.
When a government tries to erase a cultural identity to forcibly integrating a group into the greater national fabric they start by erasing that culture's language.
The British tried VERY hard to eradicate Welsh starting with the 1536 Act of Union.
The French speakers of Quebec are VERY protective of their language as an identifier of their culture inside of the greater English-speaking Canada after a couple of centuries of attempts at eradication.
And in the United States the government tried very hard to eradicate Hopi, Navajo, Chocktaw, Cherokee, and myriad other Indian languages for decades. In some cases, they were successful.
The problems start, though, when attempts to preserve a language are done for primarily political reasons, which was largely the case with the Ebonics fight some years ago.
