Yes native speakers understand older English --eth

today it is the 'th' sound in some words that is way you only hear it in some words

it is a very academic subject.

you do not hear on words like slip drop mop

but on words like make do present

if you want to do much intensive reading on the internet you can

In old English its use to denote 3rd person singular in the present tense.

Modern native users generally understand because the verb is usually makes sense if you ignore the -eth. So 'presenteth' it is understable as 'present' it.

It sounds funny to a modern native speaker to add the -eth. So in a comedy it may be that they are not using it all the time so that its still funny when used, and it will also add emphasis to a joke or scene.