Because the Muslims believe that Allāh is the proper name of God and not a mere title, they must reject that Yahweh is God’s proper name. Many Muslims will point out the similarity between the Aramaic Elah (אֱלָהּ) and the Hebrew Eloah (אֱלוֹהַּ) with the Arabic Allāh (ﷲ) and suggest that because they are cognate words sharing the consonants ‘L’ & ’H’ that they all refer to the same God, Allāh. But in point of fact, Eloah and Elah can take on plural forms (i.e. Elohim (אֱלֹהִים); Elahin (אֱלָהִין)) which Allāh cannot do according to the sources we looked at regarding the name Allāh, and what’s more is that the Aramaic and Hebrew terms are used at times in the Hebrew/Aramaic Scriptures in reference to idols (Deut. 4:28; Dan. 2:11, 47, et. al.)!
Muslims will at times resort to some very contrived linguistic exercises in order to somehow make Yahweh into Allāh. For example, Ahmed Deedat claims:
“YHWH or Yehova or Yahuwa all mean the very same thing. ‘Ya’ is a vocative and an exclamatory particle in both Hebrew and Arabic, meaning Oh! And ‘Huwa’ or ‘Hu’ means He, again in both Hebrew and Arabic. Together they mean Oh He! So instead of YHWH ELOHIM, we now have Oh He! ELOHIM.”
This could not be farther from the truth as Semitic scholars recognize that in Hebrew ‘Yah’ (יָהּ) is simply the shortened form of the divine name Yahweh. The Theological Wordbook of the Old Testament says:
“The shortened independent form of the divine name, Yah, occurs primarily in poetry and in the exclamation, Hallelu-yah, praise Yahweh. It serves also as a terminal element in proper nouns like Elijah: ’ēlîyâ (or ’ēlîyāû), ‘God (is) Yahweh.’”
Observe these words from Exodus which clearly refute the above assertion, “Then Moses and the children of Israel sang this song to Yahweh, and said, ‘I will sing to Yahweh, for he has triumphed gloriously. The horse and his rider he has thrown into the sea. Yah is my strength and song. He has become my salvation. This is my God, and I will praise him; my father’s God, and I will exalt him.” (Ex. 15:1-2, WEB). Note here that Yahweh is used synonymously with Yah and applied to both El (אֵלִי, ‘My God’) and Elohim (אֱלֹהֵי אָבִי, ‘My Father’s God’)—this does not allow for the claim that ‘Yah’ is the vocative and exclamatory particle meaning ‘oh!’
In conclusion, if we take Allāh in the sense that Morey uses it, as a simple generic term for deity then we can say that Yahweh is Allāh. In fact many Arabic speaking Christians do refer to Yahweh as Allāh in the same sense that English speaking Christians refer to Yahweh as God or Spanish speaking Christians refer to him as Dios. But if we take it (as we must in this case) in the sense that Muslims use the term, as the proper name of the one true God, then we must reject the proposition that Yahweh is Allāh.