Nepali orthography, नेपाली वर्ण विन्यास, includes a set of conventions for writing the Nepali language, including spelling, punctuation, hyphenation, Padyog Padbiyog (writing words together or separately). Nepali orthography has evolved over time. The conventions used at Nepali Language Resource Center are based on guidelines published by Nepal's language academy, Nepal Academy. Words in Nepali can be broadly categorized into two groups - Nepali words and Sanskrit loanwords used in Nepali. Sanskrit loanwords, called Tatsam, are words that have made it to the Nepali language without any modification. Nepali words include words, called Tadbhav, that originated from Sanskrit but which got modified as they finally made it to the Nepali language. Nepali words also include loanwords from sources other than Sanskrit. An important orthographic distinction between these two groups is that the Nepali words are written using Nepali writing rules, whereas the Sanskrit loanwords are written the same way they are written in Sanskrit as they made it to the Nepali language without any modification.