"Yes, I am American."
It is context sensitive. This is a thing will se in japanese a LOT. If the person you are talking to understands that now we are talking about this topic then you don't need it. は is commonly referred to as the topic marker particle meaning that it is usually only needed when changing topics.
OK - for subjects and objects I recommend you to read the following - https://en.oxforddictionaries.com/grammar/subjects-and-objects.
A topic is like bringing a particular subject, object, complement or phrase up and comments of the topic follows the topic. One would normally mark an element as a topic when
- There is a negative clause following the element.
- It is a question to the listener about the element.
- The speaker wants to compare similar elements with the topic chosen.
It is amazingly hard to explain, and topic-based languages are FUNDAMENTALLY different to subject-based languages like English. https://8020japanese.com/wa-vs-ga/?fbclid=IwAR2jqa8Z-AY4im4ZhR7y3SLt7DmNS5qWbRGB8ci6fLRf5iz0SOAIkLeocPY This article helped me wonders in my war to try and understand what the h*cc は is, if you have an open mind and are willing to accept that some languages just are different, this will be your strongest tool right now.
Why is there 人 here when you are addressing what you are? When you call yourself a student you don't use it.
Just like American (-an), British (-sh), German (-an), Dutch (-ch), teacher (-er), doctor (-or), there are a number of ways saying who you are. In this case, 学生 (-生), 先生 (-生) they both have the (-生) which means "the living." Some other examples, 看護師 (-師 nurse)、事務員 (-員 office staff)、アメリカ人 (-人 American). Just like English, not always 人.
Only with people you're close with, and then you have to use the "futsu" (dictionary) form of verbs you're using, and then it still sounds weird.
You need the "wa" to indicate what is the object of the sentence, ex: "Watashi HA, Mira-san ga sunde itta uchi o shite imasu": Yo, conozco la casa donde vivia Mira-san
Otherwise you need to change the subject of the sentence:
"kore HA Mira-san ga sunde itta uchi desu". Esta es la casa donde vivia Mira-san
ジン is the 漢音（かんのん）of 人. Copying from Wiktionary (https://en.wiktionary.org/wiki/%E6%BC%A2%E9%9F%B3): The kan'on readings are based mainly on the Chinese pronunciation in use in the areas around Chang'an (around modern-day Xi'an) and Henan, as imported into Japanese in the Nara period and the early Heian period in Japanese history, and roughly from the late Tang Dynasty through the early Song Dynasty in Chinese history.
From the wiktionary (https://en.wiktionary.org/wiki/%E4%BA%BA#Pronunciation) the Middle Chinese reading of 人 is "nyin" (Baxter–Sagart system 1.1).
I like that Duolingo likes to trick me by telling me "人" is "hito" and not "jin" when selecting it as a word brick. Even though the soundclip says jin. Looking it up, I know that this "人" can be pronounced in these two different ways, but... please don't trick me like that, it's rude.
It's trickier than that. 人 can be read as ひと, じん, にん, り or と, depending of the context in which it is written.
Something that helped me deal with kanji is this: kanji is not for reading, kanji literally has no phonetic information as English (kind of) does, it is intended to note the meaning of the sentences, and has nothing to do with the actual language.
Look, everything you have to think is this: Japanese is an spoken language, the single most important thing in the language is the SPOKEN form, the language didn't even have a written form until the 3rd century b.c, so the thing that has to make sense are the words. The kanji came from a different language, and the Japanese had to adapt the system as well as they could, to a language as inflectional as Japanese is, they used the system to break homophones and mark work boundaries, but they does not carry phonetic information. So when you find a kanji being read in a weird way, don't ask why, just add as new reading to the list xD
Just so you can understand:
When meaning "Day", 日 is read as Hi
In 日常 (Everyday, Nichijou), is read as Nichi
In 先日 (Past days, Senjitsu), it's read as Jitsu
In 日記 (Dairy, Nikki), it's read as Ni
In 誕生日 (Tanjoubi, birthday), it's read as Bi
In 生年月日 (Birth date, seinen gappi), it's read as ppi (っぴ)
In 二日 (Two days, futsuka), it's read as Ka
And in 今日 (Today, kyou), it doesn't even have an individual reading.
Just remember: kanji don't read, just represents, pictures ideas and words.
Different languages have different grammar. Like some british would say: I was sat at the chair outside the library.
Anyways, the Japanese characters usually have more than one variation and pronounsiation, depending on context. In this case, the 人 character should be pronounsed at jin. But the speaker reads it as hi tou, which is the 人 character in japanese, but means a different thing. Right?