Languages change with time and pronunciation is one of the things that changes. What is interesting about pronunciation is that direct evidence of this change exists only since we invented audio recording (XIX century).
I was looking for audio evidence of pronunciation change in various languages. In particular I'm interested in finding speeches, conversations, etc. that show how a language used to sound.
What kind of people are the most likely to have such recordings? For USA, president speeches seem to go quite back (Benjamin Harrison). For France oldest president speech I found was from much later (Paul Deschanel). For Russia I found Lenin.
I'm making the assumption that a person's accent is formed in their youth which means that Grover Cleveland is likely to have morn "modern" accent than Benjamin Harrison even though the former became president first. Is this assumption correct?