Is it permissible to overlook some errors in the articulation points (makharij al-huruf) and vowel markings (harakat) when my illiterate grandmother orally recites what she has memorized from the Qur'an, for fear of making memorization difficult for her by correcting her too much?

Reciting the Qur’an is not mastered all at once. Gradual learning is a Qur’anic and Prophetic guidance, whereby people are nurtured with smaller knowledge before larger knowledge. A beginner in learning the Qur’an, whether young or old, is permitted to recite even if they make mistakes, and they will receive two rewards if they stutter and find it difficult, provided they endeavor to learn if able. As for one who errs in vocalization, they must strive, investigate, and benefit from those more knowledgeable than themselves, and continue to recite.

One must begin by correcting errors that alter the meaning, such as clear grammatical mistakes (al-laḥn al-jalī) in vowelizations that change the meaning. The listener must correct the reciter if they make a mistake that changes the meaning.

As for the elderly, they should not be burdened with strict rules of Tajweed, precise articulation points (makhārij), or the exact pronunciation of words they are unable to master, lest they be alienated from recitation. Rather, they should be gently taught what they are capable of learning, and excused for what is difficult for them, because Allah does not burden a soul beyond its capacity. As for Tajweed rules concerning elongations (mudood) and nasalizations (ghunan), many scholars do not consider them obligatory.