Lost Language.. Lost Roots

What came to my mind when I first thought about the instance of lost languages was how we can trace languages and make connections based on the root of spoken/written words.
English is no romance language, neither are many harsher languages from Eastern lands. Many words from the various English vernaculars and regional dialects can be linked to other languages that are commonly spoken in English-speaking countries.
One language that I know has a relatively unknown origin is Euskara - which is spoken in the Basque region of Northern Spain. Euskara has served not only as a language but as a cultural tie between the Basque people. It is also a tool that the Basque region has used to gain leverage to aid their nationalist fight to secede from Spain's rule.
Euskara has no known origin in any language that is spoken today. Many have speculated and made loose connections between Euskara and other languages but none of them have turned up much.
I wonder what would have happened if the language that Euskara came from had never disappeared.
Is the loss of a language truly a loss? or could it be considered evolution of a language?
In this case, I would consider it a loss. We are simply left with nothing to connect the language to, leaving its speakers with little to identify their spoken word with.

Evolution and Extinction

Language is one of the pieces of culture that people usually don’t recognize unless they go somewhere were the language or dialect spoken is different. Not knowing the slang or popular sayings of an area can make you feel like a real outsider, so it’s more than just communication. 

Languages dying out is just part of the human evolution in my opinion. Languages are constantly changing, new ones form over hundreds of years the same as they disappear. That’s not to say efforts shouldn’t be made to preserve a language that’s dying, but if it’s just the natural order of things, there’s nothing wrong with that. Even without knowing the language of a extinct culture, one can record its history. There are aspects of language that can tell us what a culture was like, but that’s not all there is to it. That being said, a people that is being forced to assimilate to a different culture forcefully- like the aboriginals of so many countries is wrong- and in that case a language is being forcefully snuffed out, efforts should be made to preserve it.