Nothing stopping you. I do, when I'm writing. As any written communication from me is typed, only a few people know this.

Incidentally, thorn and yogh are still occasionally used today: thorn (written as y) at the beginning of some pub names, e.g. "Ye Olde Mitre Inn", and yogh (written as z) in some Scottish surnames: Menzies (traditionally pronounced "mingus"), Dalziel (pronounced "dee-el"), Mackenzie (derived from Gaelic MacCoinnich, but now with a spelling pronunciation in English).

Particularly when it's just notes for yourself. My own writing has a variety of influences, mostly for speed and legibility, used fairly inconsistently:

* (ab)uses of mathematical notation (three dots - ∴/∵ - for therefore/because; definition/solution/information become def^n/sol^n/inform^n; iff for if and only if)

* print but using ƒ for f and a cursive/rounded k

* 7 and Z have a bar (like Ƶ, to aid in distinguishing from 1/2)

* 1.8K becomes 1K8 (mostly for resistors, but occasionally 1800 in any context becomes 1K8 and 1,800,000 1M8, particularly when writing fast)

* there's an occasional touch of Japanese (mostly mo/も for as well, and ya/や for a non-exhaustive and)

Heh, when I was younger I went through a phrase of writing almost everything in Anglo-Saxon runes.

It happened to me, too. I blame Ultima IV!

I blame The Hobbit.

Ðere's no reason ðat we can't resume now! I þink ðat þeȝ look just fine!

Let’s also begin pronouncing the silent k’s... but write them with c’s and let the ‘ch’ version of c be contextual again

Haha, that would mess with people something fierce.

And juſt you wait until we ſtart uſing long S too!

You might enjoy learning Icelandic, which I’ve been told may be the closest language to old english that’s still in modern use.

Frisian is, last I checked. Some.migjt argue it is a Dutch dialect, I guess

From German to Dutch to Frisian to Scots to English is a great way to train your ear and language sense.

The great golden era blog 'Making Light' would post old English of various ages.

https://nielsenhayden.com/makinglight/archives/008591.html

Long s was cool too. Also a bummer that we stopped using past perfect in Polish some time ago.

As long as it's the long 's' and not the 'f' used as long 's'.