1a16 edit

God is the word used in Christianity, it is the actual word .... Allah is the actual word used in Islam

God is the word used in English, Allah is used in Arabic. When English people speak about the Islamic god, they use "God" too, just like they do for the gods of any other religion.

"Allah" is used very often in English to refer to the Islamic God! What rock have you been under?

the transliteration, is Arabic, the translation is of Arabic

the etymologies are different, the two words are of different cultures - Islam isn't Christianity because the two are religions, the original is of Arabic culture, belongs to Arabic culture:

https://en.wikipedia.org/wiki/Allah#Etymology

https://en.wikipedia.org/wiki/God#Etymology_and_usage

the two words root differently by way of their different etymologies, and accordingly have different meanings which are possessed by the different pronunciations, which stem from the languages they evolved in

Ok, but if you think that "God" can't refer to the god of Islam, then you need to take that matter to WT:TR.