What does the word hi, hello or hallow mean is not known to many. The word used largely and extensively in the entire world as a salutation nowadays may be 'Hello' which is derived from 'hallow' which means sacred or holy. Hi is a shorter form of hello. Saintly people and monks in the past used to Praise and worship the Almighty God throughout the day and night, in every work and action. They used to utter 'Hallowed be your Name, Father' or 'God be Hallowed' while wishing others.
This word slowly developed as a word for salutation in the past centuries. Instead of saying 'Hallowed be the Lord', they slowly started saying, hallow ignoring the meaning in the phrase.
According to some other researches, the word 'Hallelujah' (Halleluia /Halleluia /Alleluia) is pronounced to say ' Praise to the Creator' or Praise to the Lord God.
The Primitive Christians right from the beginning even during the time of severe persecutions, encouraged and strengthened one another saying, 'hallelujah'. This word while served as a salutation for the co-faithful, its main aim was to praise the Lord God always...!
This sacred way of wishing one another slowly became a word used by not only Christians but also the entire world...! So one thing is imminent, knowingly or unknowingly "every tongue praises HIS Glory" in this universe....!
Here after let's say "Halleluia" while answering the phone or saluting another ... and if not, say "Hello" thinking and believing that we are saying 'Praise to the Lord, our God'