There are multiple Qirats but Ten became very famous and reached to us with authentic narrations. Shcolars spent years to seperate and preserve the authetic Qirat narrations from the weak ones and to transmit them carefully and accurately.

The reason behind multiple Qirat is; to make Quran easier to recite and familiar amongst all the related Arab tribes. Thus, Quran came down with the multiple Qirats but in a unique way that didn’t affect its original message.

The basis of multiple dialects founf in the roots of Arabic Language itelf; the multiple dialects are spoken by different tribes and except for the major part of language they differed on some specific words. You can take British and American English’s difference as an example; though its quite different but just to give an example.
1)  Abdullah bin Kathir Al-Makki: He was the student of Imam Mujahid.
2)  Nafae bin Abdir Rehman Al-Madani: He was the student of Imam Abdir Rehman bin Qasim.
3)  Asim bin Abin Najud Al-Kufi: He was the student of Imam Abdur Rehman As-Sulami.

Ten Qirat are not like basic reading of Quran; its an entirely different subject and reuires an utmost expertise and experience. A teacher must know about the major and minor differences between all these Qirat and the accurate pronunciation of all the Qirat; as its a matter of faith and belief. Quran is not an ordinary Book and we must be carefull and senstive towards it; therefore Quran Paradise hired highly qualified and experienced teachers for this unique and dififcult course and designed a very interesting course about Ten Qirat.