Variations of these mystic terms used by the Sants turn up in Hindi and
other Indian languages. Like Naad: there is an ancient text called the
Nada Bindu Upanishad written in Sanscrit. Sanskrit forms the root of
the Indo-European Language family. Many terms of the Sants are found in
the 108 Upanishads, and those are the foundation of Indian mysticism.
Sat and Purusha are terms for God used in Sant Mat. These also are used
in the Upanishads and the Gita.
Naam, Naad, and Shabd are all used in the Adi Granth, and the Granth is
written in the Gurmukhi language. I have several translations of the
Granth and I find most of the terms and sacred names of the Masters in
the Granth. The Gurmukhi alphabet was devised during the 16th century
by Guru Nanak. The name Gurmukhi means "from the mouth of the Guru".
Shabd or Naam is the Real Guru, what is called the Shabd Guru or Inner
Master Power, the Power of God within all things. It can be heard as
Music, and this is considered the Real Name or Naam of God. The word
Shabd also is used as a term for hymn. Like for instance, the
compositions of Swami Ji Maharaj in his book Sar Bachan Radhaswami
Chhand Band are called Shabds.