[ianb]

I'd be curious if a strongly phonetic alphabet/writing leads to less changes in the sounds in the language...?

[jessaustin]

ISTM this would be difficult to study for periods that predate the phonograph? I guess one could look at rhyming poetry, but it's not clear how much that would help.

[Avshalom]

Rhymes, common misspellings, and often just primary texts talking about how words or letters sound.