Act of the Heart
Question :

As the intention is an act of the heart and not the tongue, why do some say the intention aloud while raising their hands for the Takbeer, and before the Iqamah has ended?

Answer :

There is no need for uttering the intention or saying it out aloud. Rather, it is recommended not to talk - even by pronouncing the intention - during the Adhan or Iqamah. The dislike of this is stronger in the Iqamah, and even greater if one speaks after the phrase "Qad Qamatis-Salah" is recited. It is recommended to repeat the whole Iqamah if one talked during it. People's practice in pronouncing the intention originates from the fact that the intention is a condition in worship, without understanding that there is no need to pronounce it.

The Intention of the Prayer
Question :

Is there a particular way to say the intention of the prayer?

Answer :

It is not necessary to pronounce the intention, and it is enough to perform the prayer without the pronunciation.