Hindi is spoken by about 605 million people. Hindi proper. Bhojpuri, Awadhi, Maithili and Dogri are counted separately here, though India's census folds them in, which is why you sometimes see 528 million.
On our measured language map, its closest relatives are Punjabi (Gurmukhi), Urdu and Punjabi (Shahmukhi). If you speak one of those, much of the vocabulary will feel familiar from day one.
Structurally, objects usually come before their verbs; it is written in the Devanagari script, and the course teaches the writing system letter by letter with pronunciation shown while you learn.
Every lesson is built from 2,000 real Hindi sentences, aligned with their translations word by word and piece by piece, so you always see how the sentence actually works instead of memorizing flashcards. The grammar is discovered from the sentences themselves, 1,299 patterns so far, and a spaced-repetition quiz teaches it in the order that unlocks the most of the language first. Our measured estimate for reaching conversational level from English is about 1,630 hours of study. Read how it works.
Most apps only teach Hindi through English, if they teach it at all. These starting languages already have a built course, and any other published language can be paired on request:
Speaker figures follow Ethnologue and national censuses, rounded; the difficulty estimate is calibrated against U.S. Foreign Service Institute data.