Where the 'adults can't learn languages' myth comes from
Two findings get over-interpreted. (1) Children acquire native-LIKE pronunciation more easily than adults — the brain's plasticity for phoneme acquisition declines after ~7. (2) Children are 'always immersed' — they spend most of their day surrounded by the language. Most adults can't replicate that. The myth conflates pronunciation difficulty + time-available with learning capability. Adults remember vocabulary FASTER than kids, abstract grammar BETTER, and use metalinguistic strategies kids can't access.
What adult brains do better
Pattern recognition. Adults can grasp 'verb conjugation has these 6 patterns' in a short explanation; kids need many examples. Vocabulary retention. Adults use mnemonics, etymology connections, spaced repetition. Adults learn metalinguistically — they can read about subjunctive triggers in English, then apply the rule. Kids can't.
What adult brains do worse
Native-like pronunciation. Most adults retain a noticeable accent forever — this is fine. Listening processing speed (early on). Adults usually need more listening time than kids to reach the same automatic-comprehension level. Tolerance for embarrassment. Adults often quit because making mistakes feels worse than for kids; this is a psychological problem, not a cognitive one.
Method that fits the adult brain
Explicit grammar instruction first 6 months (kids learn implicitly; adults waste time without explanations). Spaced repetition for vocabulary (flashcard cycles that bring a word back just before you forget it). High-quality listening at 0.8× speed (kids' brains adjust to native speed naturally; adults need a ramp). One language at a time (adults don't have spare cognitive capacity for parallel acquisition the way bilingual kids do).
Realistic adult timeline
Progress depends on the language, how often you practise and how close it is to languages you already know. Romance languages are usually quicker for English speakers; Mandarin, Japanese, Korean and Arabic take longer. The hard truth: a serious B2 in any language is a long-term commitment as an adult. The good news: it works.
The adult-specific motivation hack
Pick a concrete adult goal: 'I want to give my wedding toast in Spanish.' 'I want to read García Márquez in the original.' 'I want to negotiate contracts in French.' The goal that survives the long middle stretch is concrete + emotional. Generic 'I want to learn Spanish' goals die at the first hard week. Tutors who help you reconnect to the goal every month help you keep going.