Question

Assalamu alaykum

May Allah reward you for the good work you are doing in the propagation of the recitation of the Quran. Ameen.

My question is regarding the word  in surah tawbah (verse 36). Grammatically I thought it was 'tathaqaltum'.

Could you explain if this word has been changed in the recitation.

wa salaam

Answer

Wa alaikum assalaam wa rahmatu Allahi wa barakatuh. 
Jazakum Allahu khairan for the dua' and may Allah make you of the people of the Qu'ran.

The question is about the Arabic language science of  or word morphology and not related to recitation or tajweed. 

There are words like this in the Arabic language that have letters that were originally one letter, then changed into another.  They always make something easier to pronounce than what it was in the original form. The original make up of this word was indeed  , the changed into another , then the first merged into the second so we have one letter written with a shaddah (due to the ). 

There are other examples of this in the Qur’an, such as the word  in surah Al-Qamar which comes from .

If you wish to know more, you may consult an expert in the Arabic language, more specifically the science of .