That it's one of the biggest reasons why people end up getting deterred from language learning.
Using a language app like this should be used as a study compliment, not as the main method. But even as a learning app it's often downright mediocre and at worst actively teaches bad language habits.
I like exams for keeping self-study on track - DELE for Spanish, HSK for Chinese, etc - as you need practical and balanced skills. It’s still possible to end up with “exam” skills and few practical skills, but it’s better than an app alone. Exam > textbook with tutor > expansion stuff on your own.
Getting a 1 on 1 tutor would probably be the best (I've had a private Mandarin tutor via Skype for like a year), and then compliment that study with flashcards and a learning app dedicated to your target language if available (these are almost always much better than Duolingo's courses).
Nigel Richards is an absolute machine - genuinely one of those once in a generation talents, like he is to the competitive Scrabble world what someone who could run an 8 seconds 100m would be to athletics
Years after reading Stephan Fatsis's Word Freak I still think about the two professional Scrabble players who spoke only Mandarin. How did that even happen?
He should learn the language and go there. He might meet some hot women (or men).
I speak a bit of Spanish and much less French. French spelling always frustrated me, so he has that part conquered. Spanish spelling is easy-peasy compared to French (or English).