Yah, contracted from YHWH--In the Peshitta?

[Andrej]

When a Jew read the scriptures, wherever he would find "YHWH", he would read "Adonai" (Lord). It is common practice in translations (including the ancient Jewish ones, Aramaic Targums and Greek LXX) to replace YHWH and YH with a substitute. In the LXX, this is kurios (Lord), in the Peshitta (which technically is a Christian Targum) it is Maryah, in the English, this is known as LORD. This is so because the Name YHWH was not supposed to be spoken out loud according to Jewish tradition.

If we find "Adonai YHWH" or "YHWH Adonai" in the Hebrew, it was read out aloud as just Adonai. This practice is reflected in Luke 4:18, where Jesus is quoting Isaiah 61:1, but reads it as "The Spirit of the Lord (kurios / Maryah) is upon me", not "The Spirit of the Lord YHWH (Adonai YHWH) is upon me". It was therefore common in the LXX (and some Targums) to replace this with just the substitute, as else you would have "Lord Lord" in the translation. In such instances, the Peshitta uses "Maryah Elaha", in English it is sometimes written as "Lord GOD", in the Latin, it is "Dominum Deum".

The "special cases" are treated differently in the different translations, as they simply don't exactly fit the established rules. In Isaiah 12:2, 26:4, we find YH YHWH, in Isaiah 38:11 YH YH.

Isaiah 12:2
Behold, God [el] is my salvation; I will trust, and not be afraid: for YH YHWH is my strength and my song; he also is become my salvation.
Hebrew: YH YHWH
LXX: Kurios
Peshitta: Maryah
Vulgata: Dominus Deus (Nova Vulgata: Dominus)

Isaiah 26:4
Trust ye in YHWH for ever: for in YH YHWH is everlasting strength:
Hebrew: 1) YHWH 2) YH YHWH
LXX: 1) Kurios 2) Theos
Peshitta: 1) Maryah 2) Maryah Elaha
Vulgata: 1) Domino (Nova Vulgata: Dominum) 2) Domino Deo (Nova Vulgata: Dominus)

Isaiah 38:11
I said, I shall not see YH YH in the land of the living: I shall behold man no more with the inhabitants of the world.
Hebrew: YH YH
LXX: Theos
Peshitta: Maryah
Vulgata: Dominum Dominum (Nova Vulgata: Dominum Deum)

__________
Isaiah 7:7
Thus saith the Lord GOD,
Hebrew: Adonai YHWH
LXX: Kurios
Peshitta: Maryah Elaha
Vulgata: Dominus Deus

Isaiah 61:1
The Spirit of the Lord [Adonai] YHWH is upon me; because YHWH hath anointed me to preach good tidings unto the meek;
Hebrew: 1) Adonai YHWH 2) YHWH
LXX: 1) Kurios 2) missing (He)
Peshitta: 1) Maryah Elaha 2) Maryah
Vulgata: 1) Domini (Nova Vulgata: Domini Dei) 2) Dominus (Nova Vulgata: Dominus)