Assalamualaikum va rahmathullahi va barakaathuhu. Many of our Urudu speaking brothers pronounce "Allah" as though in 'Bismillah'. When they do the Azan or stand as Imam for prayers, we can make out the big difference in pronounciation. I spoke to one of my such friend and I was told that it is OK. I would like to know the ruling on that.

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.

Perhaps the questioner is referring to what may occur when the Mu'ath-thin - one who calls to prayer - pronounces the Laam of the Glorious name of Allaah with Tarqeeq (as a soft/thin Laam while it should be pronounced with Tafkheem, i.e. as a rough/sick Laam). This does not affect the validity of the Athaan. However, the Mu'ath-thin has to be keen on pronouncing the words of the Athaan correctly and give every letter the proper Tarqeeq or Tafkheem. It is disliked for the Mu'ath-thin to mispronounce it on purpose as long as he can pronounce it correctly. Scholars of Tajweed agreed that the Laam of the Glorious name of Allaah is pronounced with Tafkheem if preceded by a word ending with a Dhammah or Fat-hah (Arabic vowel marks or indicators). This rule has been underlined by Ibn Barri in his poem Ad-Durar.

However, the fact that the Mu’ath-thin mispronounces the Laam in the name of Allaah does not change the meaning; so this is merely disliked.

The Kuwaiti Fiqh Encyclopedia reads, “A pronunciation mistake that alters the meaning in the Athaan, like the prolonging of the Hamzah in "Allaahu" (by saying Aallaahu) or of the Baa’ in "Akbar" (by saying Akbaar), makes the Athaan invalid. However, if the pronunciation mistake does not alter the meaning, it is (only) disliked. This is the opinion held by the majority of scholars…”

For more benefit, please refer to Fatwa 90238.

Allaah Knows best.