Bachia, I will tell you.
Pathan, Pashtoon, Pukhtun etc are the names given to the Pakhtun tribal people of north-west Pakistan and some in Afghanistan. As with people of all races, there are variations in accents and pronunciations in different dialects. Some Pakthuns speak with a "KH" pronunciation and some speak with a "SH" pronunciation for the same words. I would guess that Quetta and Afghan people are more likely to have the "SH" variety.
So the "KH" say we are "PuKHtana" and the "SH" say we are "PaSHtana" but they are both the same race.
Usually people who are not of the Pukhtun / Pashtun race refer to them as PaTHans, I'm guessing bcos they are not used to pronouncing KH in much of their language so they take the easy way out and say PaTHaan. This is bcos the people of the rest of pakistan and india have weak tongues, due to the lack of naswaar in their early years.
Lafanter, ALexander the Great and Jenghiz Khan are NOT one and the same. Alexander was a Greek ruler who travelled the world and established a massive empire, from west to east.
Jenghis Khan was a Mongolian leader who travelled the world and established an empire from east to west. He did travel through parts of Afghanistan and you can still see the descendents of his people today, with their strongly resembling Mongolian features (not pathan tho).
There are various theories as to the origins of Pathans, some say they are descended from Alexander the Great's soldiers who settled in some areas of Swat, others say they are descended from the lost tribes of Isreal. Who knows.
As for the term "Khan", in tribal areas this term originally applied to the chief landowning families who had the surrounding labourers work the land for them, and in payment the workers received a portion of the crop. These rich chiefs who didn't have to work themselves were known as the "Khan". These days almost everyone has the name Khan as their surname, otherwise they would be known as "John, the son of James the Pathaan Naswaar Seller". However not everyone who is pathan has a surname of khan, and not everyone who has the surname khan is a pathan.
OK, that about sums it up. You should be very grateful for this answer bcos I had to read an incredibly boring book to find some information. In the end I gave up on the reading and put together bits of knowledge I already had. If anyone dares argue with what I have to say, please don't do it whilst I am in an opium induced state of mind.
Thank you kindly.
No doubt READERS should THank you too.
However , the Red lines may need reference, while others are very logical.