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There are plenty of extant languages that don't have an alphabet either. They will be "lost" in every sense of the word.

The # of languages currently spoken is typically pegged somewhere between 3000-6000 and it's thought that we lose around one a week. Most have almost no documentation whatsoever, and even so a couple papers written in the 1970s aren't going to capture any potential unique aspects of a language let alone allow for reconstruction at a later point.

The analogy to code is way off.