What is the best English translation of
abba (Greek: Αββα, Aramaic: אבא) such as in Romans 8:15? What are its senses in the original languages, and are those best captured by
daddy, or something else in English?
Not an expert, but I did have this link sent to me once:
I presume that this in reference to its use in the New Testament. In the Old Testament, it means "father". It's pretty much the only translation for it.
Use in Greek text
Essentially, it's considered more like "daddy" because it's considered more of an "infantile" word that's used. Children called their fathers abba. However, adults used the Greek word pater for "father".
ABBA is spoken in a matter a child would speak to his father before he jumped off the kitchen counter. Holding his hands out saying in faith "Daddy," knowing Abba was going to be there to catch him. It is found three times in the KJV Bible, twice used by Jesus, and once in one of my favorite scriptures, Galatians 4:6-7 And because ye are sons, God hath sent forth the Spirit of his Son into your hearts, crying, Abba, Father. Wherefore thou art no more a servant, but a son; and if a son, then an heir of God through Christ.