Adonai is not written differently in biblical Hebrew. It's just the Biblical Hebrew word for God's name is not pronounced, so Jews say "Adonai" when they come across that word.
In Hebrew? In Biblical Hebrew it would be Elohenu Eloah ehadh. Or you could say the Shema which is Sh'ma Yisrael Adonai Elohenu Adonai Ehhadh.
Yes there are.
Mesharet Adonai = משרת השם
Miles V. Van Pelt has written: 'Biblical Hebrew' -- subject(s): Hebrew language, Grammar 'Biblical Hebrew' -- subject(s): Hebrew language, Grammar
Biblical Hebrew
Because the Hebrew Bible was written in Hebrew and the New Testament was written in Greek.
Donald Broadribb has written: 'The dream story' -- subject(s): Dreams, Psychoanalytic Interpretation, Traum 'The Structure of Biblical Hebrew Poetry' 'An attempt to delineate the characteristic structure of classical (Biblical) Hebrew poetry' -- subject(s): Bible, Biblical Hebrew poetry, Hebrew language, Hebrew poetry, Biblical, History and criticism, Language, style, Metrics and rhythmics
Adonai means "the Lord", but the rest of that phrase doesn't apear to be Hebrew.
I think that by Hebrew Scriptures you mean the Tanakh. In this case, it is Biblical Hebrew
Adonai
There are many Hebrew names for God. The most common are Adonai and Elohim.
It is a non-Jewish spelling of the Hebrew for The Lord of Hosts (Adonai Tsevaoth).