「Japanese sentence structure」
「Identifying and describing people and objects」
「a」（As for myself.）I am John Harris. （Introducing one-self）
「b」 I am (the one whose name is) John Harris.
Watashi wa Jon Harisu da/desu.
Watashi ga Jon Harisu da/desu.
The first example （１）watashi ("I") is followed by the wa particle ("as for"), which marks it as the topic of the sentence, and (b) uses ga in order to mark it as the subject of the sentence. Usually, the topic (wa) comes at the beginning of a sentence, which establishes what that sentence is about. In the case of wa the topic is required to be something, or someone, that both speaker and listener can see, hear, or identify from previous conversations or knowledge. The subject (ga) is different in where the doer of the action, the person, or the object in the state expressed within the sentence. The main difference being that the person, or object is newly introduced into the conversation, or is emphasized .
"I am John Harris" is a translation that is effective for both usages of wa and ga. However, the meaning is different based upon the particle that follows watashi. While the sentence with ga is emphasized (so as to introduce himself as John Harris) the sentence with wa is not (due to the fact John Harris is introducing himself to someone). Sometimes, the difference of usage between wa and ga is complicated. More specifically when the subject, and topic are the same as in (1) where no direct emphasis is given; often a sentence can include both a subject and a topic, in which case both particles have distinct functions from one another. Also, in certain cases the subject is not marked by usage of ga, but by wa.
Personal pronouns ("I," "you," etc.) in Japanese have a multitude of forms (dependent on the the gender, and desired speech style [formal, plain, rough, etc.] the speaker decides to utilize, for the specific situation they are in. The gender specificity is a cultural hold-over from feudal times, and earlier, and while that is the rule of thumb, there is a precedent for females using the more "male-oriented," expressions of one-self and others. The very formal, and polite forms of "I," (Wataskushi, and Watashi both of which share the kanji of 私) or "you," (though no very formal variant of "you," exists, the polite form of "you," being anata・あなた), are available to everyone, traditionally, the plain (boku・僕/Kimi・君) and rough forms (Ore・おれ・Omae・お前), are for usage by men.
While third person (singular) pronouns exist in Japanese ("he," Kare、and "she," kanojo), and are not limited by speech forms, regardless of situation, it is suggested refraining from using them when referring to social superiors, or young children. Also, the pronoun (ano hito, "that person") can be used to mean "he," or "she," it can carry negative nuances.
The plural forms of personal pronouns are simple enough to where you only need to add the suffixes -tachi or -ra; ("I," watashi-tachi・watashira, boku-tachi・bukura, "you," kimi-tachi・kimira, etc. The suffix -gata can replace -tachi for the sake of politeness; anata-gata. Both suffixes can be used with certain nouns; gakusei-gata ("Students"), sensei-gata ("Teachers"), etx., although the suffix could be omitted from the word in Japanese, as long as the intent of the speaker, or sentence is clear. The usage of da or desu at the end of a sentence is the English equivalent of "am," "is," or "are." Da is the plain style of speech, commonly used among family and friends, while desu is the polite form commonly used among adults who are not close friends.
I am an American.
Watashi wa Amerika-jin desu.
She is a nurse.
Kanojo wa kangoshi da.
Tom is a student.
Tomu wa gakusei desu.
He (newly introduced) is the person in charge.
Ano hito ga tantōsha desu.
Sarah (not Linda) is a dietician.
Sara ga eiyōshi da.
That marks the end of part 1, hopefully it helped you in understanding the way the Japanese language handles sentence structure, part 2 will be in the near future, hope to see you there!
ʿʿ˅⁽ˆ⁰ˆ˺ ⁾˺ こゆうきあいはら ʿʿ˅⁽ˆ⁰ˆ˺ ⁾˺