Most every language has two-syllable words that are often the first words a baby speaks:  DaDa, MaMa, PaPa.  For the infant Jesus it was Abba.  As an adult He taught us to address God that way.  It is hard for me to call God Daddy.  I think that God needs aloof titles that express His exaltation.  But Jesus came to bring God near.  When the Spirit of the Son comes into our hearts He moves us to this nearness, crying out through us, “Daddy!”

“Because you are sons, God has sent forth the Spirit of His Son into our hearts, crying, ‘Abba! Father!’”  Galatians 4:6 (NASB)