Fatha

The use of the vowel fatHa (or in English "a") simply refers to the participant as being the one receiving the "action" as opposed to the use of kasra (or "i" in English) which denotes the participant "doing" the action rather than receiving it.

The "B" letter has a fatHa vowel mark which makes it "Ba," the 'h" letter also has a fatHa vowel with an "alif" letter connected to it, so it is "haa" and the "hamza" (or you can call this is an "alif") has a kisra vowel mark and a "ya" letter connected to it which makes it "ee."

In this case the spelling Qua'ran should present hamza without a carrier sitting on the line because the vowel of hamza is fatHa (a) and the preceding vowel is a a^([sic]) long uu (waaw)

I'm not sure why you have added an "a" at the end of jahannam or reduced to the first fatHa (a) to a kasra (e).