There are a few things that Duolingo dont teach you: its gives your something to train, and got some sort of a score system, but why some conjugations are like they are, its dosnt explain ..
When I learn languages, at first I like they to explain me what are the grouping of verbs, in groups that are conjugated similarly.
Much later on, when I'm already very familiar with the language I might enjoy etymological explanations about how those conjugations came to be.
But I consider that an advanced subject.
Why is the word for the color some times bevor and some times behind the main word? Why is it some times une and some times un .. ..
By main word, you mean the noun it qualifies ?
I'm not sure about colors. I think it depends on whether it's short (then it's likely to come before) and whether it's very often used (then it's likelier to come before).
But it's a mystery. I'd say the general case would be to put it after the noun.
"une" is the indefinite article for feminine nouns, like "eine"/"einer" in German.
"un" is the same for masculine words, like "ein","einen","einem","eines" in German.
French does not have a neutral gender.
And when you change languages a word that is masculine in your language may be feminine in the other one.
That is relatively random, but there are usually some list of terminations than can give hints.
I think the feminine is sometimes a different form altogether (like "soeur" is the feminine of "frère"), but often are derived by
adding suffixes to masculine words,
like "-ine", "-esse", etc.
Once you know a noun is masculine or feminine, then you know whether you should use "un" or "une" before it. But you can't assume the gender is the same as in German or any other language.
I found that i make the best results when i found a logic behind the things, some times french gramatics follows a logic, but you first have to find it out yourself what the logic is ..
There is always some logic, and then there's always some chaos. It's the result of a large number of people optimizing how to speak about things.
They usually have general rules so they don't have to remember fancy details for every single use. But there are a few expressions that are used so often than people have them burned strongly in their minds, and they don't need rules.
And then there's English.
It might help to think that languages are not designed (except Esperanto, logjam, or so...) but evolved.
So there's not someone setting up rules and everyone following it.
There's people doing what they want, and linguists trying to find some logic in it by writing general rules (and exceptions).
In French some of those linguists are called immortal but they still die thinking people should speak as they say, despite everyone just speaks as they can and want.
The rules are not guides but mnemotechnics. They minimize effort for speakers, but not necessarily for learners.
The more your learn a language the more things make sense, and the more you forget the that some things just don't make sense, precisely because you already remember them.
It's a little like word length. Most often used words in a language are usually short, and less usually used words are longer.
It's the same you would do when designing a compression code.
Now why Germans say "Entschuldigung" for "sorry", "désolé", "perdón", "scusi" is almost hinting that they think they'll never be wrong and have to use it.
It's also similar to "semantic resolution". Languages usually have more different words with narrower meanings for concepts their speakers use more often.
Like the inuit having a lot of words for different kinds of
snow or ice, because it's useful up there.
In shool back then whe had to learn first the whole Conjugation stuff by memorize, so maybe i have to use also an French Learn Book beside Duolingo, also some words are still not in my mind, like the French Word for Frog and for Cow etc..
I haven't used duolingo, but why all means, yes. Get a French grammar book, or maybe a French textbook. You can also use the web, I think the keyword is FLE (Français comme Langue Étrangère?).
Im still on my Learning Projekt but its not that easy..
It doesn't have to be easy, it has to be fun.
Another issue is that because everyone whit an Truck Drivers License can Deliver Stuff in the EU, even if he dont speak the Language of this Country i have lots to do whit Drivers who only speak Bulgarian, or Polish or other stuff i cant speak .. so i would not be able to get every language in my Livetime i would need, so i think i will get French and maybe some other..
I've never heard there's a limit to how many languages you can learn. I've heard that the more languages you've learnt the easier it becomes learning new languages, but of course there are many languages, and I think nobody has ever been able to speak them all Unless you believe in Adam and Eve).
If you learn a few languages, then you increase the chance that someone you meet speaks one of those, even if that's not their native language.
You'll never learn them all, but you can keep learning languages as long as it's fun.