How do we scientifically respond to the specious argument that the vocalization (tawqit) of the Qur’an led to a change in the meanings of its words, and thus serves as proof of its distortion?

The dotting of the Mushaf by the Tabi'un (successors) is a manifestation of Allah's preservation of the Qur'an. Scholars were raised up to make it easy for common people to recite it correctly after the spread of linguistic errors. Dotting did not alter the Qur'an; rather, it clarified the differences between similar-looking letters. The fear of some common people making linguistic errors or mistakes does not contradict the preservation of the Qur'an, as the people of knowledge promptly addressed the problem through dotting.