Short answers, pulled from the story.
Devanagari is an Indic abugida script used for over 120 languages, making it the fourth most widely adopted writing system in the world. Its most widely spoken language is Hindi. It also serves as a primary or secondary script for Marathi, Sanskrit, Nepali, Konkani, Maithili, Sindhi, and dozens of others.
The script was in regular use by the 7th century CE and had reached its modern standardized form by around 1000 CE. Its oldest recognizable precursors appear in the 1st century CE Rudradaman inscriptions, and its ancestor, the Brahmi script, dates to the 3rd century BCE.
The name combines the Sanskrit word deva, meaning heavenly or of a god, with nagari, which derives from nagara, meaning town or city. It is commonly translated as script of the divine city or script of the city of God, though the precise significance of the deva prefix remains a matter of scholarly debate.
The horizontal line running along the top of Devanagari letters is called the shirorekhā. It is one of the script's most recognizable visual features and helps group letters belonging to a single word.
The Tibetan script was invented by Thonmi Sambhota in the 7th century CE, based on the Nāgari script used in Kashmir. He added six new characters to represent sounds that did not exist in Sanskrit. Thonmi Sambhota was sent to Nepal by the Tibetan emperor Songtsen Gampo with instructions to find a writing system suitable for the Tibetan language.
The leading academic standard is IAST, established at the Congress of Orientalists in Athens in 1912, which uses diacritics to map Sanskrit sounds to Latin letters. Other systems include ISO 15919 (codified in 2001), Harvard-Kyoto, ITRANS (version 5.30, released July 2001), the Velthuis system developed in 1996, ALA-LC romanisation approved by the Library of Congress, and WX, developed at IIT Kanpur for natural language processing.