If saying the ayats melodiously changes the meaning, it nullifies namaz, too. To recite the Qur'an melodiously means to prolong its letters in order to tune them to musical notes. For example, it changes the meaning to prolong the letter (a) as in "Alhamd-u-lillahi rabbil." Likewise, saying "Rabbanalakalhamd," as some muazzins do, changes the meaning. For rab means stepfather; so instead of saying, "We thank our Allah," they say, "We thank our stepfather." If the meaning is not changed, namaz does not become nullified. But if you extend such vowels as Alif, Waw and Ya too long, namaz becomes nullified, even if the meaning is not changed. As seen, if saying the words melodiously does not change their meaning, if the letters are not prolonged as long as two letters, and if it is intended to beautify the voice and to embellish the recitation, it is permissible. In fact, it is mustahab to do so when performing namaz as well as when not performing namaz. It is written in the fatwa of Abussuud Effendi: "If the imam's singing becomes 'amal-i kasir, or if he prolongs one letter as long as three letters, his namaz becomes nullified. To say something melodiously means to sing it, to repeat your voice in your larynx so as to produce various sounds."
