"I know this kid!"
Translation:Je connais ce gamin !
Gamin/gamine and enfant should be accepted, they should be interchangeable in this sentence, especially since there is no additional context.
However gamine/gamine may more often be used when on familiar terms with someone, and enfant may be a little more distant/formal and more direct translation of "child" or "baby" instead of "kid"
This is one of the many reasons why you should use as many resources as possible when learning a new language. Duolingo won't ever be absolutely perfect, and that is no one's fault. Language is complex, full of depth, ever changing and adapting, and may completely vary in pronunciation and meaning depending on who you are talking to and when. But unfortunately Duolingo's hiccups like these cause people who rely on its accuracy to become too focused on a specific word or sentence they got marked "wrong", when a lot of the time it is not wrong at all, just a different answer because language is subjective. Us learners begin to feel lost, confused, and think that we have been misunderstanding the target language entirely because we have these little hiccups here that don't make sense. These flaws in Duolingo prevent us from looking at the language as a whole and take time away from us focusing on more important things like culture, immersion, verb conjugations, and grammar. Because we are learners who want to understand and immerse ourselves to the best of our ability we get thrown for a loop when a little hiccup like this happens and get hung up because we want to achieve comprehension.
Don't get beat up. Learning any new language is hard and when you are using a software to do so there may be bugs or answers that aren't "correct". But Duolingo can't define what is "correct" in a language, it just needs to give you a right or wrong so you can learn and progress, because that is what the app is for. It needs to give you something to base your learning off of, its giving you a foundation for your French and in this case Duolingo decided to use "gamin/gamine" in place of "enfant". This doesn't mean enfant is incorrect in the real world, on the streets of France, in your French class, or talking to a native speaker you would be understood either way.
Learning a language requires attention, perseverance, dedication, patience, and critical thinking. Practice listening, reading, writing, speaking, and thinking in the target language. Use books, comics, TV shows, movies, YouTube clips, songs, speeches, audiobooks, magazines, articles. Use language learning apps like Duolingo, Lingodeer, Memrise, and others. Paid or free, you can find lessons, tutors, and softwares to help in supplement to everything else. You can speak with native speakers in your target language or travel to that country/place and use what you know, and what you don't. Mistakes are a part of learning, and you will most certainly pick up things that you didn't know before by trying to speak/live in your target languages' country. Most importantly though, no matter your budget or ability, you can literally use anything to help you: You can even read labels on things at the store like food or soap!
You don't EVER get worse at something from practice. If you continue to practice, you will get better. But you need to practice in a variety, and not solely with Duo. Using multiple resources and or apps will create a more cohesive understanding of the language and allow you to enjoy it more by adding a variety to your studying.
Keep going, guys. Remember that languages are complex, beautiful creatures. You WILL get to where you want to be on your language learning journey. DO NOT let big red X's and "incorrect" marks stop you from understanding and trying your best. DO NOT let fear and uncertainty dictate what you want to do and learn. Remember why you wanted to learn the language. Remember that you are doing this for the betterment of yourself. Look out the window and realize there is an entire WORLD out there, with people speaking hundreds of thousands of different languages. And that someday, you will be able to communicate with someone else out there, somewhere, too. I am always praying for everyone who is trying to learn a new language, you are all in my thoughts! I believe in you! Who knows, maybe we will see each other and be speaking fluently in our learned language together one day :)
What you see as flaws are merely the methods that Duo teaches you that there really is a different level of register for both French and English. Some people consider only "child" as being the appropriate word to refer to a young person. They would never lower themselves to say the word "kid". Others are perpetually in an informal/familiar mode of speech. They use "kid/kids" all the time. They would never use "child" because to them it sounds too formal and stuffy. Both hold to an limited worldview that does not consider how ingrained their formality and informality has defined them. Duo encourages you to recognize both and to use the different terms appropriately.
If English was not my second language and I belonged to a different culture, I would or could have translated this sentence into... je connais cette chevre... which would be the exact translation from English to French... so may be it is important sometimes to be more flexible in teaching a language.