English: God.
Spanish: Deos.
German: Gott.
Chinese: Shen.
French: Dieu.
Hebrew: El or Elohim.
Greek: Theos.
Latin: Deus.
Russian: Bog.
People who don’t understand the concept that different languages use different words for the same concept are remarkably ill-informed.
As you say, this is the word that was used by Arabic speaking Christians before Mohammed was born.
The word Christ used to refer to God when on the earth was in Aramaic pronounced very close to Allah, as can be seen here:
http://www.peshitta.org/cgi-bin/lexicon.cgi
Take a look at the Hebrew and Aramaic words and note how close they are to Allah, especially given that many centuries have elapsed. They’re essentially the same word in these closely related languages.
I am not addressing whether the Person referred to by the Hebrew, Aramaic and Arabic terms is the same, but that’s a completely different issue from whether the words have the same meaning.
In Chinese, “Shen” can also refer to any false god; any idol. It must be marked specifically when used for the True God, which is usually done by leaving an extra space before the character for Shen. In Hong Kong and Taiwan, most editions of the Chinese Union Version, 1890 (the most widely used Chinese translation) uses ShangDi for the True God and Shen for false gods.