Although you do make a valid point that indeed native tongue is very important, but the Blood link is just as important as the cultural, traditional, and lingual aspect, if not more.
Regarding Yusuf "Pathan" of india, well anyone these days can slap a "Pathan" or "Khan" next to their first name, i have met quite a few people who have done so and claimed to be "Pathans/Pashtuns", however only a real Pashtun can prove his ancestry through providing important background info like Tribal lineage, for example my Mother is a Yusufzai because my Maternal Grandfather is a Yusufzai, however my Maternal Grandmother is a Barakzai, my fathers side is Shamozai.
Although we might have lost the ability to speak the native tongue of our ancestors, we haven't lost our identity, and not everyone has the same definition, or qualification, or criteria of/for being a Pashtun.
Secondly, i'm not sure what one would consider these Sikhs who speak Pashto and probably know more about Pashtun way of thinking then i do since they have been living in Peshawar amongst Pashtuns for centuries after fleeing persecution in Punjab. Do they become Pashtuns?
Sikhs and Muslims live in harmony in Peshawar - YouTube
I'm certainly not a Punjabi, Kashmiri, Sindhi, Mohajir since i cannot trace my ancestry to any of the latter groups mentioned, than what am i?
