Yah is a shortened form of God's Name.
Jesus' name in Hebrew is Yahshua Yah is God, Shua is Salvation God Saves
Hallelujah (Alleluia) is Halleluyah in Hebrew
Hallelu Yah means Praise be to Yah the one true living God.
Elijah is Eliyahu in Hebrew and means My God is Yah. He was sent to turn people back to the pure worship of YHVH (Gods Holy Name).
The endings of the prophets names in English is iah. This came from Yah in Hebrew.
Haggiah is HagiYah
Hezekiah Is HizkiYah
Matthew is MattitYahu
Nehemiah is NechemYah
Obadiah is OvadYahu
Zedekiah is TzedekYah
Zephaniah is TzfanYah
Jacob is Yaakov Jacob (Yaakov) was born grasping the heel of his twin brother Esau (Ackov). Jacobs name spelled in the Hebrew is the same as Esaus except for one letter. The letter Yod which means hand is the first letter in Jacobs name and represents the hand grasping onto the heel of Esau.
Isaiah is YeshaYahu
Joshua is Yahashua When Moses placed his Hands upon Hosea, he imparted his spirit and authority to him and his name was changed to Joshua (Yahashua) by the additon of the letter Yod to the front of his name. This changed his name from Salvation (Hosea) to Adonai will save (Joshua).