I’ve been learning Japanese more consistently for a few months now and something I’ve noticed that slows down the learning process is you don’t just learn a direct translation of a word, you need to also learn:
Whether it’s written in Kanji or hiragana/katakana
How to say something in a more or less formal way for different situations
Cultural aspects (e.g. in Japan it’s considered rude to be too direct, you you usually need to find a more roundabout phrase to communicate your meaning!)
Japanese is one heck of a challenge, but a worthwhile one!