Both の and こと turn verbs into nouns, but they feel different:
————————

こと is more conceptual and abstract. It treats the action as a general idea and sounds more detached. It's often used for information, ideas, or facts.

の feels more direct and personal. It points to the actual action as it happens. It sounds more immediate, and it's commonly used for things you directly see, hear, feel, or control.
————————

→ 私は死ぬことが怖い = "I'm afraid of death"
Here, the action is treated as a general concept.

→ 私は死ぬのが怖い = "I'm afraid of dying"
This feels more immediate and personal, as if you're afraid of dying rather than death as an abstract idea.
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The difference becomes clearer with direct perception. When you directly witness something, you usually use の.

→ 私は子どもが泣いているのを見た = "I saw a child crying"
What you saw wasn't the concept of a child crying—you saw the action itself.

The same contrast appears with hearing, especially when comparing direct perception and reported information.

→ 火山が噴火したことを聞いた = What you heard was the news of the volcano erupting.
Here, you received information about the event.

→ 火山が噴火したのを聞いた = You were there when the volcano erupted. You directly heard it.
In this case, you experienced the sound itself.
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Finally, when talking about actions you can directly control, の is usually preferred.
→ 酒を飲むのをやめた = "I quit drinking"

Here, the action feels concrete and personally managed rather than abstract.
————————

Quick rule of thumb:

Directly experienced / immediate / personal → の
Abstract / conceptual / informational → こと

Source: part of this video: [www.youtube.com]

家 can be read two main ways:

いえ is closer to house. Kind of refers more to the building itself
うち is usually translated as home. Includes the deeper connections to family and personal history inside the building.

家(いえ) is more used for the house in the literal sense - physical walls and objects that make up your house.

Use お家 when talking to someone else about THEIR home. If that person is above your station (like your boss) you should use お宅.

For your own home use うち.

いえ generally means "my house, the building" while "うち" is "my home, where I live".

There are many types of HOUSE styles, I.E. (いえ) cottage or Victorian.

Yay(Ie), im home after a long day

Freind: "Wow! You're house is so pretty- the paint job is so well done!"

Me: "#Ie! Ie! (Which means no and sounds like "Iye") That's not true."

I love being at home, these four walls are my empire so when I get back in my house I say "YE!(いえ) Here I am!"

This is a more formal version of で (de), which is often used in announcements, etc.

More formal than で

Since どこ is a question word, it can't be marked with the topic marking は.
Note: It's not grammatically impossible, but it's very unnatural in real usage.

Where to, doc?

Person を Event に 誘う→To invite a person to an event

Eg: ジョンさんはマリさんを映画に誘いました。→John invited Mary to the movies.

Event に 遅れる→To be late for an event
Eg: 授業に遅れてはいけません
→You cannot be late for class.

You に (need) to be here AT 12!

Just for information, へ / に are used to MARK location. They are locations where the action is GOING. Whereas で is used where the action is HAPPENING/TAKING PLACE.

いる　to be, to exist (of animate objects)
ある　to be, to exist (of inanimate objects)
おる　to be, to exist (of animate objects - humble)

aru or iru = AI (artificial|not alive or intelligence|alive) ***imperfect expected motion, sorry***; present negative form is いない (inai). iru is ichidan & aru is godan

Conversational contraction. しているんだ。ー＞　してんだ。

re: sense 3

Confusingly, ん after the negative stem of a verb can be both a contraction of the negative ない / ぬ ending, or of the archaic volitional む ending -- which have completely opposite meanings.

Fortunately the volitional ん verb ending (which is a different dictionary entry, flagged as an archaism) is rather uncommon in modern speech and mostly restricted to specific grammar patterns or intentionally formal/stylistic use of archaic language, so you don't often have to guess whether what looks like a negative is actually a positive.

For the first meaning, ん is most likely not a contraction of いる after the て form but rather a contraction of る.
In the case of ～ている, the contraction is done in two step:
～ている -> ～てる -> ～てん

And that last る -> ん contraction can also be use with verb ending in る like:
する->すん
来る->来ん
It's particularly common when combined with the particle な (the "not" one) for comical effects in casual conversation between friends. As in:
すんな (DON'T do that!)
来んな (DON'T come here!)
One of my favorite example is:
"話しかけてくんな"
Which is quite rude but gives a "Don't you dare come to talk to me!" vibes between friends. That the kind of feeling it can creates (so be careful with that).
Other than that, the ら->ん contraction is also possible as in:
分からない -> 分かんない
Which is relatively common too in casual speech between friends.

I tried to search for some formal explanation but couldn’t find anything that could give me a final answer. Apparently, it could be either some kind of dialect or a general kind of contraction where the entire ラ行 (the ら, れ, る, り, ろ sounds) and な行 (the な, に, ぬ, の, ねsounds) can be replaced with ん. At that point, I gave up because both feel correct and I couldn’t access to more information (nor can I still read research level article… for now). I pretty sure some of those ん contraction are really common mainly because of the kansai dialect combined with manzai comedy for example. But at the same time, I also feel like native used that contraction a bit randomly trough Japanese history. Hence why you have that damn ん which can mean either る、ら、に、の、ぬ、etc. I got traumatized by that ん when I first started to talk with some japanese friends and also when watching youtube. Hope that explanation will help you at least a bit for that (Also now, it’s fun and ん contraction + kansai ben + manzai → best way to make Japaneses laugh)

PS : Just remembered another one but I’m not redoing the entire explanation for that, so I will just leave that here :
やるのか？→ やんのか？ (“wanna fight ?” with a fake yankee vibe kinda, very common between friends)
So, that る → ん contraction can theoretically be applied to any verb with a る ending but in practice, it’s not used everywhere. Like, it’s not common in standard written Japanese, it’s not really “grammatical” either but it’s still extremely common in casual spoken Japanese (especially in those expression). So yeah, don’t know if that explanation is useful or confusing anymore but at least, you will be aware of them if you encounter those expression in the wild x)

In casual speech, だ is often dropped, but だ is not dropped in だよ and だね. (Genki II)

Used after Nouns and な-adjectives. Not used after a verb or い-adjective.

教師
General word for “teacher” (profession). Neutral, used in writing or formal contexts.

先生
Polite title for a teacher (and doctors, etc.). Used when addressing or referring respectfully.

教員
Formal/official term for teaching staff (used in schools, documents). More bureaucratic.

教授
“Professor” at a university. Specific rank/title, higher than regular teachers.

教諭
Licensed teacher at elementary/junior high/high school. Official job title within schools.

先 = ahead
生 = (in) life

A teacher is someone who shares their experiences gained from typically being older than you.

Teachers came to life 生 before 先 students .

Teachers (先生) teach you everything you need to know before (先) you start life (生) away from your parents

せん せい
"Sen, say what three plus three is now or it's no lunch for you."

The second kanji almost looks like a smaller version of the first one. The first one is the teacher, the second, smaller one is the student trying to copy him. His form is a little different though, he still has things to learn from his sensei!

Before 先 moving through the birth of life 生, you should consult a せんせい

My astrology 占星 (せんせい) teacher 先生 (せんせい) is called Sen「せん」and always says「せい」weird things.

kanji: teacher's previous life

Our teacher's 先生 name is Sen「せん」.
He always arrives to class *before* 先 us and always *ahead* 先 of us.
He likes to say「せい」 that knowledge will be useful in life 生.

The 2nd meaning is short for なさい, and is usually mentioned in the flat-tone, in contrast to the 1st meaning/usage which is usually mentioned in a rising-tone.

食べな = Eat up. (from 食べなさい) (such as a command made by a parent)

食べるな = Don’t eat!

"~な" has two seemingly conflicting meanings of "do" and "don't" because ”~な” can be used as a contraction of either (1) "~なさい" (i.e., "do") or (2) "~ない" (i.e., "don't").

To distinguish the two:
(1) ~なさい only attaches to the い-stem of verbs or to the base of an ichidan verb (e.g. これをたべな = "(do) eat this"). So, if you see ~な after a verb's い-stem, it indicates a command to do something (as なさい).
(2) However, ~ない can attach in all other cases, i.e. after the dictionary form of a verb and/or after a complete logical clause (e.g. これをたべるな = "don't eat this"). So, if you see ~な outside a verb's い-stem, it indicates a prohibitive command (as ない).

NAH (な), DON'T do that

一体 (いったい) – noun sense:

a) One body / same body (同体), emphasizes inseparability. E.g. 三位一体.

b) Unity / becoming one (一丸), group or elements acting as one. E.g. チームが 一体となって 戦う.

c) As a whole / overall (一体に), evaluating or describing something in its entirety. E.g. 一体に日本人は 愛国心 がある.

Source: [www.weblio.jp]

Ouch (ita)! What the heck did you do that for?

あっち こっち and そっち are used when there are TWO things to choose between (THAT one or THIS one), whereas あれ それ and これ are used for ONE item or MORE THAN TWO.
(Japanese From Zero Course/Book 1 Lesson 2)

この　cannot stand alone and must be used with a noun

これ　works as a placeholder and is its "own thing"

I liked what one comment said: you can remember the difference by thinking of この　containing the の, like you are saying "これ　の　_____"

[www.reddit.com]
[www.nhk.or.jp]

Difference between この and これ:
この is adjectival and cannot be used on its own. It's always "pointing" to something. (Ex. このラーメンは美味しい). A way to remember this is that この is using the possesive の, so it literally means ___ of this.

これ however acts more like a noun an can be used on its own in a sentence. (Ex. これは美味しい).

In conclusion, without context, この would mean "this __" or "this one __" and これ would mean "this".

This answer right here is Correct

"Come (ko) here! Are (re) you interested in buying this?" says the Sellsperson showing you their wares (to visualize an item near the speaker)

This curry (said in a Northern English accent)

-what is THIS you eating?
-THIS is KOREan noodles

This ray gun right here, next to me, is not a uni-ray. No. You share This specific ray gun. This is a CO-RAY これ

KORE did THIS, I swear!

Klose to me. Use ko. Close to Someone else. Use so. That Alien over there. Use a.

Generally with positioning there's a pattern.
The first kana is position:
Close to me こ
Close to you そ
Far from both of us あ
The second kana shows the word:
This/that れ
Here/there こ

This is a contraction of the particles で + は.

それでは -> では -> じゃ

Used in じゃあね and じゃあまた

When compared to なぜ, どうして has more of an emotional component to it, and is more often used in spoken speech.

*𝗛𝗼𝘄* does bread "dough stay"「DŌSHITE どうして」dense when it's cold? *𝗪𝗵𝘆* doesn't it rise?

Why is this どおしてp so high that I almost stumbled over it when I entered the room?

how/why / for what reason (どう = query {...}) + did you DO SHIT (して ('to do' Te-form))?

Do she take (doushite) the gold this way? Says the detective.

Starts with こ so this words is used to refer to things that are closer to the speaker. So it means "thins kind"/"like this"

こんな - "such thing" meaning this specific thing
こういう - "such things" that are like this one, that one and other things of the same sort

In anime you often hear things like こんな女！

What kind of? (どんな) This kind of (こんな)

A con like this?! Such na-rve!

2 is mainly 遣う and 使う is not really used for 2 (at least in theory, doesn't mean that even native won't make the mistake). So, 遣う is not just an alternate (hence why つかう is marked as middle school reading for 遣). Here is a JP definition that I found for 遣う:
人形・動物などを自分の意図どおりに動かす。あやつる。《遣》
NB: From one dictionary to another, the definition vary a bit but overall, 使う and 遣う are considered as different words.

I BOUGHT(かう) it so I have to USE(つかう) it.

I took out (TSUKAU) the thing in order to use it.

つ is for tools, かう is for cow = Gary Larson's infamous "cow tools" comic

You need to sow some seeds in a large field but all you have is a large, heavy, metal plow. How are you going to use it? Easy! All you need are two (つ) cow (かう)s. That'll make using it a breeze!

SCOWL with concentration when using things.

You have to make (作る) the desk (机) before you can use (使う) it.
Or: if you can remember that angel also uses this Kanji (天使), think "angels live in the つかい (sky)."

I'm gonna USE this TO SUE a COW.

A scout (つかう) can use anything as a tool in the wild!

When I use a tool I often SCOWL (TSU KA U)

I needed to scour (つかう) through my tool box to find something I could USE to fix the problem.

Tsuka (from the last airbender) is always using tools to make up for his non-bending

eagle SCOUT using the kanji

Scouts (tsuCOUts) know how to use their tools.

Although the potential form of つかう is つかえる and is listed as transitive, the grammar actually changes based on the idea you’re trying to convey as to WHY something is or isn’t usable. In English we would use a passive form or a non-verb for the same object where Japanese instead simply declares it to be the が marked subject and keeps the same verb.

E.g.

I can’t use this device (because I don’t know how) = I が device を 使えない

I can’t use this device (because the device is broken) = the device can’t be used = device が 使えない

“The device can’t be used” is passive in English but the Japanese is not passive here so it may help to think of it as “the device does not behave usably” to match the active voice

There is also かしら, which is the female only version of かなあ

I wonder if this is in Kana (かな). Ah (あ), it is!

can I? ...I wonder...

This guy had a dark aura (だから) so I stopped inviting him to the barbecues

He is allergic, so/therefore I left out DA KARAts (the carrots)

だ: is
から: from
≈ according to

"so, therefore, like i already said... that is why DA KARATE chop is so popular"; だ (what was stated marker) + から (from)

So, are you going to the Dakar (だから) rally? (Dakar rally it is a famous rally from Paris to Africa)