To keep a name starting with those alphabets which were governed by the special constellation of the moon at the time of birth of your child. Whenever a child is born his or her horoscope is calculated on the basis of date time and place of birth. At the specific time the child is born under a specific Ascendent and during this exact time placement of the moon and the sun is under a certain sign and constellation. Moon's constellation is considered very important for keeping the name of the child.
There are 27 constellations and each has four divisions. It is said that in every constellation when the moon passes it produces a certain vibration. If we keep the child's name matching that cosmic vibration chances of his or her success or more. This child is believed to be always in the best of his or her luck from health wealth and other aspects of life.
For example if a child is born under Anuradha constellation first division, The name should be kept from 'NA' alphabets.
Similarly second division NI Third division NU fourth division NAE starting letters or vibration of the name should be above from the under Anuradha constellation and so for all 27 constellations different starting letters are recommended.