Did Allah speak in the Holy Quran using Arabic letters, and what is the meaning of "Allah's speech, with sound and letter, does not resemble the speech of creation"?

The Holy Quran, its words and meanings, is the speech of Allah, the Blessed and Exalted. He truly spoke it with the Arabic letters and conveyed it to Jibreel, who then delivered it to the Prophet (peace and blessings be upon him). These letters that we recite are the speech of Allah, but the how of His speaking it is unknown, for Allah does not resemble anything in His creation. As for our recitation and speaking of the Quran, that is our action and is created. The belief of Ahlus-Sunnah is that the Quran is the uncreated, revealed speech of Allah. From Him it originated and to Him it returns, and Allah truly spoke it. It is not permissible to say that it is a narration or an expression of Allah's speech; rather, it is truly the speech of Allah, even if people recite it or write it. Speech is primarily attributed to its speaker, and it is the speech of Allah with both its letters and its meanings.