|Morning Blessings: A Pleasant Tone|
Whoever reads from the Torah without a pleasant tone, or recites Mishnah without song, Scripture says about him (Ezekiel 20:25): "I gave them decrees which are not good, ordinances
with which they will not live." (Megillah 32a)
"Without a pleasant tone", meaning without life and warmth. Then, the natural consequence is that one will fall asleep; and the Sages teach us that sleep is one sixtieth of death. (Torat Chacham)
Torah has to be sung. The point is not that one needs a professionally trained voice in order to escape the punishment of "with which they will not live".
Rather, if someone reads or learns Torah in a monotonous way, if he fails to hear the music of Torah and rattles off verse after verse without connecting to its beauty, he will if not literally, at least figuratively fall asleep.
When we say in the Morning Blessings "Sweeten... the words of Your Torah in our mouthes", we are asking God to help us "read Torah with a pleasant tone and recite Mishnah with song". When we recite in the Blessings of the Shema "for the sake of our forefathers... to whom You taught the decrees of life, so may You be gracious to us and teach us", we are praying to access the music of Torah in order to truly feel alive.