The Hebrew word "עֶבֶד" is related to the Arabic word "عبد" and to the Aramaic word ܥܒܕܐ (ʿaḇdā). These words mean "servant" or "slave".
The Greek word pais derives from the Hebrew עֶבֶד ebed, which bears the primary meaning of servant, or slave.
Hence, the primary translation of pais theou is “servant of God,”
with “child” or “son of God” being an extravagant embellishment.
According to the Theological Dictionary of the New Testament, “The
Hebrew original of pais in the phrase pais theou, i.e., ebed, carries a
stress on personal relationship and has first the sense of ‘slave.’
This
is all the more interesting because it dovetails perfectly with the
prophecy of Isaiah 42:1, upheld in Matthew 12:18: “Behold, My servant [i.e.,
from the Greek pais] whom I have chosen, My beloved in whom my soul
is well pleased …” Whether a person reads the King James , New KJ
Version, NRSV, or NIV, the word is “servant” in all cases.
Bonus:
Here's how to write "slave of God" in Aramaic (the language of Prophet Jesus) with transliteration:
ܥܒܕܐ ܕܐܠܗ
(abda d'Alah)
Note that the Aramaic script is written from right to left (as Arabic & Hebrew), and the transliteration represents the Aramaic characters using the English alphabet.