[zarzavat]

This is why “oldest language” is silly.

Is Old English the same language as Modern English? They are definitely not mutually intelligible. If we can accept them as being the “same” language then why not English and Proto-Indo-European? It’s not like people woke up one day and started speaking a different language. It’s a continuous evolution.

The oldest languages that are still intelligible such that you could go back in time and be sure to be understood are surely the liturgical languages like Arabic and Latin that have been carefully preserved over thousands of years. Without this system of active remembrance, languages naturally become unintelligible with their prior versions.

[LordGronk]

I think a better and more interesting question would, perhaps, be “What is the most conservative language as supported by written and spoken evidence (the variations of ancient greek dialects tracking with orthographic differences shows that it can be done). And Anglo-saxon is not the same as modern English to any degree. 1066 and the great vowel shift saw to that. A great book on the history, and conservative nature of Egyptian is “The Ancient Egyptian Language: An Historical Study” by James Allen. If you really want to get into the weeds “Ancient Egyptian Phonology” by the same author. The latter in particular points out the extreme similarities to more rural Coptic dialects and Egyptian as found in the Heqanakht papyri.

[avhception]

It's interesting to think that the amount of written and spoken words that will be preserved for future generations is higher than ever. Will the future need to understand all these internet texts, podcasts and videos contribute to the ossification of languages?