I feel like after couple weeks observation, I could understand the 1100s or 1200s version well enough, but it probably helps that I have vague memories of high school German classes. Speaking it would take far longer.

I’ve taken french, spanish and latin. None of which would help me with much older English. I’m pretty good with figuring out context but I’d probably have a really hard time with anything older than 1400-1500. Canterbury tales for example in the original English is really hard to read and there’s a lot of words that make no sense to a modern only English speaker.

Whan that Aprille with his shoures sote

The droghte of Marche hath perced to the rote,

And bathed every veyne in swich licour,

Of which vertu engendred is the flour;

Whan Zephirus eek with his swete breeth

Inspired hath in every holt and heeth

The tendre croppes, and the yonge sonne

Hath in the Ram his halfe cours y-ronne,

And smale fowles maken melodye,

That slepen al the night with open yë,

(So priketh hem nature in hir corages):

Than longen folk to goon on pilgrimages

(And palmers for to seken straunge strondes)

To ferne halwes, couthe in sondry londes;

And specially, from every shires ende

Of Engelond, to Caunterbury they wende,

The holy blisful martir for to seke,

That hem hath holpen, whan that they were seke.

Early English sounds like a Kneecap song.