Do not misunderstands me. This is just linguistic equivalence. That is not to say that the character of God, the laws of God, the nature of God is just the same in Islam, Judaism and Christianity. Not at all.
I think the Islamic idea of God is seriously distorted. In his Regensburg Lecture in 2006, Pope Benedict XVI used the Greek word "Logos" for God, which is, of course, found at the beginning of the Gospel of John, and translates "Word," connoting reason as well (the root word of "Logic".)
Benedict asked, in all sincerity, whether "reason" was a common basis for dialogue (that root-word "logos" again) between religions, and sectors of the Muslim world responded with rioting across 3 continents, leaving 19 dead.
Which was an answer, of sorts.
Arabic speaking Jews do NOT substitute the word allah in the Shema. Heaven forbid. Many classic Jews texts are written in Arabic, but the Shema does not use this phrase. Jews say Shema in Hebrew, even when not speaking Hebrew.