Claim: According to the 2011 census, Nepali and Hindi had the first and second rank of the highest number of second-language speakers in Nepal, wherein the official language is also Nepali, formerly called Khas-Kura.
Evidence: Hindi is spoken as a first language by about 77,569 people in Nepal according to the 2011 Nepal census, and further by 1,225,950 people as a second language. 
16 million (2011 census)
9 million L2 speakers (2011 census) Over the centuries, different dialects of the Nepali language with distinct influences from Sanskrit, Maithili, Hindi and Bengali are believed to have emerged across different regions of the current-day Nepal and Uttarakhand, making Khasa the lingua franca. Dialects of Nepali include Acchami, Baitadeli, Bajhangi, Bajurali, Bheri, Dadeldhuri, Dailekhi, Darchulali, Darchuli, Doteli, Gandakeli, Humli, Purbeli, and Soradi. These dialects can be distinct from standard Nepali. Nepal
India It is the official language of Nepal and one of the 22 scheduled languages of India. Also known by the endonym Khas kura (Devanagari: खस कुरा), the language is also called Gorkhali or Parbatiya in some contexts. Outside India, Hindi speakers are 8 million in Nepal; 863,077 in United States of America; 450,170 in Mauritius; 380,000 in Fiji; 250,292 in South Africa; 150,000 in Suriname; 100,000 in Uganda; 45,800 in United Kingdom; 20,000 in New Zealand; 20,000 in Germany; 26,000 in Trinidad and Tobago; 3,000 in Singapore. 
According to the 2011 national census, the percentage of Nepali speaking people is about 44.6%. Maithili is the second most spoken language in Nepal at 11.67%. Most of the languages in Nepal are endangered because out of the 129 languages, only 19 of them have more than 100,000 speakers. Maithili (/ˈmaɪtɪli/; Maithilī [ˈməi̯tʰɪli) is an Indo-Aryan language native to the Indian subcontinent, mainly spoken in India and Nepal. 33.9 million (2000)
(only 13.58 million reported their languages as Maithili on the 2011 census of India, as many consider it to be a variety of Hindi