This is confusing, since "nibbana" is not a Sanskrit word at all, but rather a Pali word. Or, at least, it is the standard English transliteration of the Pali word transliterated as "nibbana", just as "nirvana" is the standard English transliteration of the Sanskrit word transliterated as "nirvana". Do "nirvana" and "nibbana" actually denote the same thing? In English, "nirvana" seems to have won out. But what about the words in other forms of Buddhist text in many other languages, in different alphabets yet again? Do the standard transliterations of these terms in Chinese translations of earlier Pali and Sanskrit texts use the same transliteration for each, for example?