"Your car is small."
I find from a learning perspective that sentence tend to include あなた for structural purposes (you should replace あなた with the person's name if you know it). The Tips and Notes for Intro 2 say:
Pronouns are relatively rare in Japanese, but they are sometimes used to explicitly specify the subject or topic of a sentence. Below are some of the most common ones.
あなた is used in polite settings, however, if you know someone's name, it's best to call them by their name, typically followed by さん or せんせい。
Maybe the speaker is mocking someone for having a small car, but since Japan is the land of the kei car, driving a small car is usually more convenient than a big car for driving down narrow streets, parking, and even for tax purposes (kei cars are taxed at a lower rate). There are different contexts, so different answers are possible.
The omission of desu here is informal, and they don't know their name if they're using anata. I can only conclude that they're using the rude sense of anata and being all snobby. "Your car is so small. My car costs more than your salary for 4 years. Do people actually use this sad excuse for a car? Did I mention that my car is expensive and I have money? My car is expensive. I have money. "
your car is smol
Maggie-sensei has a good article about when and when not to use anata.
I think people take "it's more polite to use a person's name than anata" to the extreme to mean that using anata is always rude, and that is not true. To me this sounds like something my friends would say to me if we were planning a car trip and I offered to drive. I wouldn't be offended to be called anata, and I drive a kei car, so I'd have to agree with them that my car is in fact small.
It does sometimes have a very personal feeling in Japanese, in a bad way.
One way or the other, the Japanese tend to specify by name etc rather than saying you, he, she, the person there etc...
It would be very normal in Japanese to ask Wolfgang what Wolfgang is doing, by name.
There is a stereotype of wives calling the husband あなた, especially the older generation. (Not sure how much truth there is in it.) But for the same reason, a single woman would probably be very careful to not use it toward a male friend or coworker even in the least formal situations.
They both function because of wheels.
馬車(ばしゃ) is the carriage pulled by one or more horses, 自転車 (じてんしゃ) is a bicycle, 台車 (だいしゃ) is that flat, wheeled thing used to move heavy stuff, and 人力車(じんりきしゃ) is called rikša here where I live, a vehicle pulled by a man. 水車(すいしゃ) is a watermill, 風車(ふうしゃ) is a windmill. 歯車 (はぐるま) is this thing ⚙, I don't know the English word for it.
The thing you don't know the English word for: do you mean a gear? It looks like a gear. Could be a round saw (not sure if this is a compound word or not), though? You can use these sample words to see if one of them is what you were looking for. :)
Thanks for breaking all that down for us!
The riksa thing there (I can't type the symbol above the s) might be a rickshaw.
Also, it is most likely a gear cog because they have "teeth", and that's probably why the kanji for teeth is there, as well as car; maybe it's because it is part of a car, or it has a circular motion like a wheel....
Usually Japanese word order can be pretty free as long as you keep the words attached to their particles, but with words attached to the の particle this is not true. あなたの has to come in front of くるま, because that is the word it is describing. If you wrote くるまはあなたのちいさいです (kuruma wa anata no chiisai desu), then あなたの describes the word that comes after it, which is ちいさい. You're saying, "car is your small", so in order to say "your car is small", you have to say あなたのくるまはちいさいです.
I did more research, and it seems like car dealers use お車 a lot, and Weblio gives several examples using it, so I think it should be accepted. I wouldn't say that using お車 has to do so much with it belonging to someone else, but rather it's a very formal way to speak. Several of those Weblio examples are translations from The Great Gatsby, a book about wealth and high society, while others use sonkeigo, the next level up in politeness from what Duolingo teaches. In normal polite conversation, I think most people would just say 車.