The Sanskrit phrase used in India is not mentioned originally in the bodies of the two main Pure Land sutras. It appears in the opening of the extant Sanskrit Infinite Life Sutra, as well as the Contemplation Sutra, although it is a reverse rendering from Chinese, as the following:
The apostrophe and omission of the first "A" in "Amitābha" comes from normal Sanskrit sandhi transformation, and implies that the first "A" is omitted. A more accessible rendering might be:
A literal English translation would be "Bow for the sake of Amitābha Buddha". The Sanskrit word-by-word pronunciation is the following;
While almost unknown, and unused outside of the original Sanskrit, the texts provide a recitation of Amitābha's alternate aspect of Amitāyus as;
A literal translation of this version would be "Namo Buddha of Infinite Life". Other translations may also be: "I pay homage to the Enlightened One immeasurable" or "I turn to rely on the Enlightened One immeasurable".
As the practice of nianfo spread from India to various other regions, the original pronunciation changed to fit various native languages.
"I take refuge in the Tathagata of Unobstructed Light Suffusing the Ten Directions".
The latter was originally popularized by Shinran's descendant (and Rennyo's ancestor), Kakunyo, but its use was greatly expanded by Rennyo.The Meritorious Dharma Gate of the Samādhi Involving Contemplation of the Ocean-like Marks of the Buddha Amitābha"