Spoken by around 240,000 people, Otomí is an important native language of Mexico. The Otomís are said to have inhabited central Mexico since long before the Nahuas entered the region.
The Otomís are a fascinating people with a long history, and many still hold onto their ancient traditions and religion. The Otomís may have been among the first peoples to cultivate many of the New World plants like tomatoes and chocolate, which are now consumed all over the world.
On a personal level, my girlfriend's family is of Otomí origin, and learning this beautiful language would help me to connect better to her and to her family.
There are variations between dialects (not huuuuuuge variations, but still variations). The names that they call their language seem to vary a lot, but this is because, as I understand it, some groups call the language a version of 'speaking' and some a version of 'good' (like 'the language of the good people')
Languages like this are very useful for work in the public sector as well. I have known a couple of social workers here in the states and learning a Native American language can open up entirely new doors on who you can help and what you can experience. People fail to realize how many elderly people born in t his country don't know English.
Duolingo must add Otomi as a language to learn same with Nāhuatl, Cachiquel & Kekechi to some extent (probably not going to), Miskito, Garífuna, Totonaca & Huasteca. Glad they are going to add Quiche & Yucatec Maya, disappointed cuz they added High Valyrian & Klingon which are made up languages & pointless to learn & Esperanto has no native speakers or is a national or even minority language anywhere (I may be wrong). Damn I speak too long & yes I am half indigenous veracruzano (other half Middle Eastern)
Mexico has a fascinating mix of Spanish and indigenous cultural influences. Adding indigenous languages of Mexico would be great.