Transliterations
In English the mantra is variously transliterated, depending on the schools of Buddhism as well as individual teachers.
Most authorities consider maṇipadme to be one compound word rather than two simple words. Sanskrit writing does not have capital letters leaving capitalisation of transliterated mantras varying irrationally from all caps, to initial caps, to no caps. All caps is typical of older scholarly works, and in Tibetan Sadhana texts.
Read more about this topic: Om Mani Padme Hum