Why Does Your Grandma Call it ‘Worshington’ with an Unnecessary ‘R’?

Do you have one, too? Yeah, I think most of us do.

Not just my grandma, but many have older family members who had an "R" to words like wash or Washington. I was going to find out why this happens, but I'm not coming up with any hard evidence.

The term non-rhotic kept coming up, though.

Adjective
non-rhotic

Of an English accent: not pronouncing the written letter "r" unless it is followed by a vowel.
In a non-rhotic accent, the word 'farther' is pronounced like the word 'father'.
via Wiktionary

On the other hand, I have a friend adds and R at the end of words ending in vowels like he'll say, "Canad'er," for Canada.

Some say it's a regional thing, but my grandma is from the area so that wouldn't be the cause of it.

If you have any insight, tell me in the comments. In the meantime, I'm just going to regard it as habit.