The demonstrative pronouns point out objects.
*Yon (thon) indicates something that is further away in space or time than that or thae.
This is a braw day.
This is a beautiful day.
This dug's awfu frichtsome.
This dog is very fearful.
Thir's guid neeps.
These are good turnips.
That hoose is gey an braw.
That house is very nice.
That'll dae fine.
That will do nicely.
Thae's bonnie weans.
Those are pretty children.
Thir fowk canna thole the cauld an thae fowk disna like the sun.
These people can't bear the cold and those people don't like the sun.
Yon ben is happit wi snaw.
That mountain over there is covered
Yon's a muckle tree.
That's a big tree over there.
Thon wis grand times.
Those were great days - long ago.
In Mid Northern and North Northern Scots this and that are used as plurals rather than thir and thae.
This hooses is aucht the laird.
These houses belong to the landowner.
That tuips is awfu veecious.
Those rams are terribly vicious.