People with high IQ's may not be good language learners

I somehow disagree with the assumption "People with high IQ's are good language learners". People with high IQ's are known to be the ones who do the IQ test faster, more accurately and logically than others. However, learning a language is a long process, not just a test and the one who succeed in the test may be a good language learner but may be not, depending on many aspects like strategies they chose, the situation they are in.
There are some hurdles that will cause more trouble to intelligent people than a person with lower IQ's. One of the hurdles is that when they know how smart they are, they may feel afraid to take risks and make mistakes. According to the lesson, "A good language learners are those who are willing to look ridiculous". In order to acquire a language, a good learner need to feel free to make mistake and learn from it, which is quite hard for highly intelligent people. Let's take Francois Gouin as an example, as a language professor, he chose a safer way to learn German by staying in his room, memorizing words, phrases and grammars but in the end, he failed to understand a single word attending lectures or speaking to a German.
Language acquisition requires a considerable number of skills, strategies, practice and motivation. A smart person without any motivation or practice will not be able to master a language. Being smart is just an advantage learning a language but not a must. An average person with high motivation, keep practicing and find time to learn and reflect everyday can be a good language learner as well. When I was a student, I was considered to be a good language learner when I got high mark in any grammatical tests and good vocabulary memorization. However, I graduated from high school without any ability to speak to a native speaker. My hand kept shaking and my mouth was so hard to open when I met my first foreign teacher in a language center. I was so shy to speak and at that time I knew I hadn't been a good language learner as I used to think and my way of learning had been so wrong.
Motivation is also a more influential factor in learning a language than intelligence. My experience learning Japanese can prove this. After mastering English, I started learning Japanese but after 10 years, I'm still struggling with it as my motivation to learn it is not as strong as I used to be with English. I always feel I can learn very fast and even faster now than I was 20 years ago starting English but the lack of consistency causes me trouble as I keep lacking and just be back with Japanese when the language becomes rusty enough to learn from the beginning.
In conclusion, having high IQ's has something to do with language acquisition but it's not everything. In order to learn a language, learner needs a combination of motivation, skills, good strategies, practice, consistency, and also a good teacher.
https://www.coursera.org/learn/english-principles/peer/EeE39/essential-question-peer-review/review/YAY4wjYsEeaQlwqCQEbvsw