13 One must distinctly pronounce the holy name
When chanting, one must very distinctly pronounce the maha mantra:
Chanting involves the activities of the upper and lower lips as well as the tongue. All three must be engaged in chanting the Hare Krsna maha mantra. The words “Hare Krsna” should be very distinctly pronounced and heard. Sometimes one mechanically produces a hissing sound instead of chanting with the proper pronunciation with the help of the lips and tongue. Chanting is very simple, but one must practice it seriously.
– Sri Caitanya caritamrta Adi lila 17.32
If one has chanted distinctly during his life, it is quite possible that even at the time of death he will be able to chant with faith and love:
While the body is fit, one should chant the holy name of the Lord loudly and distinctly. If one does so, it is quite possible that even at the time of death he will be properly able to chant the holy name of the Lord with love and faith.
– Srimad Bhagavatam 6.2.49