Did You Know? Abba

Why did Jesus in prayer address Jehovah as "Abba, Father?"
The Aramaic word "abba" can mean either "The Father" or "O Father". On each of the three occassions that the expression appears in the scriptures, it is part of a prayer and is used in reference to the heavenly Father, Jehovah. What signifigance does the word carry?
The International Standard Bible Encyclopedia states "In the colloquial speech of Jesus' time, abba was primarily used as a term of informal intimacy and respect by children to their fathers. It was an endearing form of address and among the first words a child learned. Jesus used this expression in a particularly fervent appeal to his Father. In the Garden of Gethsemane, just hours before his death, Jesus in prayer addressed Jehovah with the words "Abba, Father." Mark 14:36
"Abba" as a form of address to God is extremely uncommon in Jewish literature of the Greco-Roman period, doubtless because it would have appeared irreverent to address God with this familiar term, continues the above mentioned reference work. However, Jesus, use of this term in prayer is an indirect attestation of His extraordinary claim of intimacy with God, his Father. The other two scriptural occurences of Abba both in the writings of the apostle Paul indicate that first century christians also used it in their prayers. Romans 8:15, Galatians 4:6