Quote Originally Posted by Martialartsnovice
Question: What languages officially are recognized as dead or outdated, how are people today able to learn them. I know Latin has played a part in the formation of modern Spanish, Italian, French. Ancient Greek evolved into the modern greek spoken today.

IS it possible though to piece together a shall we say a Asian Latin or Greek that could be like the Rosetta stone in translating ancient Egyptian.
Dead languages are usually defined as having no native speakers anymore. There is some ambiguity, though: Eg. Latin as such is dead, but has never died. As you said, it evolved into several other languages. & what we now learn as Latin, is only a snapshot of that language at a certain time/era.

As we are not sure about every detail of Latin pronunciation, we know even less about ancient Egyptian. We know the consonants from their hieroglyphs, but almost no vowls.

Latin & Egyptian are fairly easy to reconstruct in comparison to other "dead" languages which don't have a written record, but reconstruction is possible even for a language like Proto-Indo-European. What we then have is no more than an educated guess, though. The same should be possible for Japanese. But I don't know how reliable the guess-work for proto-Japanese is.

I just googled for proto-Japanese & found some 800 results. I suppose, you should do the same & judge for yourself whether you find the proposed ideas convincing.