Everyone hits a plateau. The difference between those who succeed and those who quit is motivation strategy.
Motivation follows action
Waiting to feel motivated before studying has the relationship backwards. Starting is what generates momentum; the feeling arrives after the first few minutes, not before them.
Make the entry point small enough that it survives a bad day. One exercise still counts, and it keeps the habit alive until enthusiasm returns.
Pick a reason that is yours
'It would be useful' rarely survives a busy month. Reasons that hold up are specific and personal — a family you want to talk to, a country you are moving to, a book you want to read in the original.
Write the reason down somewhere you will see it. When the novelty wears off, that sentence is what keeps the habit in place.
Expect the plateau
Early progress is fast and visible. Somewhere in the intermediate stretch it flattens, and it feels as though you have stopped improving. Almost everyone quits here, and almost nobody needs to.
What is actually happening is that gains have shifted from obvious to subtle — nuance, speed, comprehension in noise. Changing the input often helps: new material, a harder podcast, a real conversation.
Use streaks carefully
A streak is a good servant and a poor master. It is excellent at protecting a daily habit and unhelpful when a broken one makes you abandon the language entirely.
Decide ahead of time that a missed day is a missed day. Restart the next morning — the only streak that ever mattered is the one you are on now.
Make it social
Learning alone is quiet work, and quiet work is easy to drop. A partner, a class, or anyone who will ask how it is going adds a small amount of accountability that outperforms willpower.
Using the language with a real person is also the clearest reminder of why you started — which is, in the end, the most durable motivation there is.