The Book gives its own picture of a parent teaching a child
Look at what Luqman does, because it is the only extended scene of its kind in the Book.
He speaks. That is the whole method. He calls his son my son, repeatedly, and then he reasons with him, about the worst thing a person can do, about prayer, about what to do when things go wrong, and about not turning his face away from people in arrogance.
And then, at the end of it, there is an instruction about voice. Be moderate in your walking, and lower your voice. A course about shouting turns out to have a verse about volume, sitting inside the Qur'an's model of how a parent teaches.
Qur’an and Sunnah
وَإِذۡ قَالَ لُقۡمَٰنُ لِٱبۡنِهِۦ وَهُوَ يَعِظُهُۥ يَٰبُنَيَّ لَا تُشۡرِكۡ بِٱللَّهِۖ إِنَّ ٱلشِّرۡكَ لَظُلۡمٌ عَظِيمࣱ
Luqman counselled his son, ‘My son, do not attribute any partners to God: attributing partners to Him is a terrible wrong.’
Qur’an 31:13
يَٰبُنَيَّ أَقِمِ ٱلصَّلَوٰةَ وَأۡمُرۡ بِٱلۡمَعۡرُوفِ وَٱنۡهَ عَنِ ٱلۡمُنكَرِ وَٱصۡبِرۡ عَلَىٰ مَآ أَصَابَكَۖ إِنَّ ذَٰلِكَ مِنۡ عَزۡمِ ٱلۡأُمُورِ
Keep up the prayer, my son; command what is right; forbid what is wrong; bear anything that happens to you steadfastly: these are things to be aspired to
Qur’an 31:17
وَلَا تُصَعِّرۡ خَدَّكَ لِلنَّاسِ وَلَا تَمۡشِ فِي ٱلۡأَرۡضِ مَرَحًاۖ إِنَّ ٱللَّهَ لَا يُحِبُّ كُلَّ مُخۡتَالࣲ فَخُورࣲ
Do not turn your nose up at people, nor walk about the place arrogantly, for God does not love arrogant or boastful people
Qur’an 31:18
وَٱقۡصِدۡ فِي مَشۡيِكَ وَٱغۡضُضۡ مِن صَوۡتِكَۚ إِنَّ أَنكَرَ ٱلۡأَصۡوَٰتِ لَصَوۡتُ ٱلۡحَمِيرِ
Go at a moderate pace and lower your voice, for the ugliest of all voices is the braying of asses.’
Qur’an 31:19
Translation: M.A.S. Abdel Haleem, The Qur'an, Oxford University Press, 2004.