وَمَنْ سَمِعَهُ فَزَعَمَ أَنَّهُ كَلَامُ الْبَشَرِ فَقَدْ كَفَرَ
Whoever hears it and claims it to be the speech of a human has disbelieved.
The statement concerns a denial of the divine origin of the Qur’an. Calling Allah’s revealed speech a human composition rejects its true source.
Speech of Allah and human speech are not interchangeable descriptions.