Who was the ancestor of Turkic tribes ?

Turkish speakers among the Iranian population who were spread through every region of Iran were not Persians who were forced to abandon their original language and forgot it and learned Turkish. No one spoke Turkish as a result of being vanquished by the Turkish conquerors over their lands, as was the opinion spread throughout Iran; the Turkish speakers are nothing but the descendants of the Turks who had migrated in ancient times from Turkestan in search of safety and pasture and became conquerors of Iran and spread throughout it and settled here and there in tracts of land and mingled with the population over the course of time and intermarried with them and followed them in their customs and clothing and religion, although they have preserved their Turkish language and their descendants still speak it (although there are some of these Turks who have assimilated into the indigenous population and have forgotten their languages as well.

Proof of our claim, in addition to what has been outlined above, comes from the history books. To force a people to abandon the language into which they had been born and to forget it and to speak a foreign language against their will and to carry this to extremes–in this, the Arabs were supreme. They defeated the Iranians and captured their princes and kings and uprooted their rule and ruled over their lands and stripped them of their independence and spread among them their Islam and their Koran and governed them for centuries on end and made Arabic the language of letters and the Court and prohibited the people from writing in any other language and settled among the defeated two or three thousand poets and scholars and had them teach Arabic and spread it and habituated some hundred thousand writers with this language; but despite all this, the Arabs were never able to get the Iranians to repudiate and abandon their Persian language and exchange it for Arabic. This is in addition to the differences between the two sides in appearance and distinctions in sensibility and character, which cannot be explained except by a difference in race and ancestry with the native population. We do not claim that the people of Azerbaijan or all speakers of Turkish in Iran are pure blooded Turks/racially pure etc etc but nethertheless are Turks.

Now the Turks never outlawed Persian or forced Turkish and Turkification upon the population, this was never a policy, so you must look at the logic of these claims and realise how ridiculous they are. If the Turks could so easily brainwash everyone into speaking Turkish and thinking that they're Turks how is it humanly possible that the whole of Iran today isn't Arab as the Arabs ruled for centruries and outlawed all other languages and had a strong Arabization policy?