why left handed persons writing speed is comparatively faster ?

Because we write from left to right, right handers pull the pencil, writing away from their body while left handers have to push the pencil, writing towards their body. Teaching left handed people to write the same way as right handed people can make handwriting slow, uncomfortable and messy.

I have multiple guesses but no precise answers.

Guess one: anatomy + physiology = it's quicker to write underhanded letters and loops while using the right hand to steady the paper.

Guess two: lefties tend to be smarter and/or use more of their brains. so it makes sense they could write notes quicker.

A lefty whose parents and kindergarten teacher "made her" go right. ;)

I can write very quickly. I can't always read it afterwards but meh...

I don't so much write as scrawl, and it's a real time saver.

Good question, although I don't know the answer. And you're right, my dad was left handed, and it didn't slow him down at all, he was a quick writer.

we excel at everything thanks for noticing