This question may sound deep on the surface, but it falls apart because it is built on a big historical and theological misunderstanding.
The premise assumes that Islam claims God only speaks Arabic, or that Arabic is the only language of divine revelation. But in reality, both Islamic theology and secular history teach the exact opposite.
If we check mainstream academic books such as “The Aramaic Language of Jesus” by Dr. Sebastian P. Brock, or we check Angel Sáenz-Badillos's “A History of the Hebrew Language” these mainstream scholars proved
that the historical Jesus taught in Galilean Aramaic, while Moses received the Torah in Biblical Hebrew.
Even according to Christian and Western history, the Divine has always spoken to prophets in the native language of their direct audience. Arabic is simply the continuation of this exact historical pattern for the final Prophet, who happened to be born in Arabia.
To say "Allah only speaks Arabic" is to completely miss how the concept of divine speech works. If you look at profound African Christian scholarship, particularly Professor John S. Mbiti's book which he titled: Concepts of God in Africa, it was meticulously documented that African societies possessed a deep understanding of a single, supreme Creator long before foreign intervention.
Whether they call Him Olodumare, Chukwu, or Modimo, the Creator understands and hears every human being in their indigenous tongue. In Islam, a person can make personal supplication to Allah in Yoruba, Zulu, English, or Mandarin, and it is perfectly understood and answered.
This is why I make bold to say that the choice of Arabic is not a matter of cultural supremacy, but a brilliant masterclass in global sociolinguistics.
One book I find interesting here is Peter Trudgill's Sociolinguistics which he called: An Introduction to Language and Society.
He pointed out that, any global movement requires a foundational standard language to keep its core message from fracturing into thousands of conflicting interpretations over time.
Just as English serves as the universal language of global aviation today so pilots from Nigeria and Japan do not crash into each other, Arabic is preserved strictly as the universal language of Muslims’ ritual prayer.
It is a global stabilizer that ensures a Muslim from Lagos, a Muslim from Beijing, and a Muslim from Rio can stand in the same row and pray in perfect, beautiful unison without a single language barrier.
I hope this help clears your misunderstanding and confusion.
Allah knows best.