Prayer: Why Is 'Ṣalāh' Pronounced with a 'H' in the Adhān Instead of 'T'?

Practical Laws of Islam as per the teachings of Imam Khamenei

Prayer: Why Is 'Ṣalāh' Pronounced with a 'H' in the Adhān Instead of 'T'?

English:

Question #460:

We know that the word "ṣalāt" [prayer] ends with "t" but in adhān it is said: "ḥayya ‘alaṣṣalāh" [hurry up for prayer] ending with "h". Is this correct?

Answer #460:

There is no problem in ending the word "ṣalāt" with "h" while stopping at the end of the word. Rather, it is obligatory.

-Imam Khamenei, Practical Laws of Islam, Importance and Conditions of Prayer