This is such a huge misconception. Actually, I think this one of the main reasons that Muslims are looked down upon. People think we're worshipping another god besides what they know of as God. I would love to explain this to every single nonMuslim on earth if I could.
But I can't. So I'll explain it to you instead.
Allah is God.
If you believe in God, you agree with this concept.
"God" is an English term. In France they call God "Dia." In Italy, "Dio."
In Arabic, "Allah."
I know you may feel very attached to the word "God," but keep in mind that Jesus never uttered the word "God." He did not speak English.
Allah is simply the Arabic word for God.
The name Allah literally means THE God.
Arab Christians and Jews call God "Allah" as well. Not just a Muslim thing.
When I first converted, to be honest, I couldn't get over the difference between the words Allah and God. I didn't feel like I had a real connection to Him when I used the term "Allah," but as I came to understand the word, I realized I like it better than "God."
The word God was not uttered by any prophet. It doesn't have any profound meaning in English.
It's beautiful to me that Prophet Muhammad (saws) spoke Arabic and used the word "Allah." Who cares what it is in English?! The Quran mentions Allah in Arabic for a reason.
Forget about the word though, the more important part is the concept. What the word means. I know it may be hard to put aside in your mind that Allah is God in another language, but just try.
Try to realize we are all brothers under the same God. Allah. Rabb. Dia. Dio.
I don't care what language, we all belong to Him. Whatever you call him. Whereever you live. Whatever language you speak. If only everyone on earth could have this understanding.