I've previously mentioned the て form of verbs, they are very useful, not just because of the grammatical structures you can make with them, but also because the た form of verbs, follows the same pattern

for example

the informal of 食べます[たべます] is 食べる[たべる] (to eat)

its て form is 食べて[たべて] (eat, imperative form)

it's た form, is its informal past form, 食べた [たべた], this may seem simple now, but when you see the groups of verbs, it'll be very useful, because you won't really need to study the た form separately from the て form

for example

来る[くる]
and
切る[きる]

may have different written forms, but it's easy to mix up their て forms, because they are 切って[きって] and 来て[きて], so if you're hearing them, you might get them mixed up

so remember to check out content like Japanese news (https://www.youtube.com/watch?v=coYw-eVU0Ks) or other spoken media, like movies, to get used to listening Japanese

中 means "in the middle", or "inside", it can be used to mean "in the middle of [doing X]", for example 電話中です [でんわちゅうです] "I'm on the phone" (or "I'm in the middle of a phone conversation")

はず is used to say "supposed to" or "should", for example 今、勉強中のはず [いま、べんきょうちゅうのはず] means "[I] should be studying now"

I reduced the messages to one while I'm making some new content, I'm gonna go over the verb groups, this is relatively short, but I find it really useful for some of the next things, after that I want to go over the て form, then the た form (which is basically just the past form of the verb, in "dictionary form" which is informal, but always used in that form, when used for this sort of sentences), to then go to 'verbed nouns' (I don't know their official name, but it's like "food prepared by Mom" for example), and some other interesting stuff with grammatical times/tenses, the verb groups is just a list, so I'll go over that quickly with some examples, of each verb, and populate the lists with verbs as we go

you can use the て form of a verb to form sequences of actions, for example, あれをやめてあそこへ行きましょう [あれをやめてあそこへいきましょう] "stop that, [and] let's go over there"

you could also "chain" for longer sequences, for example, あれをやめて、これを食べて、あそこへ行きましょう [あれをやめて、これをたべて、あそこへいきましょう] "stop that, eat this, and let's go over there" or "stop that, and eat this, then let's go over there"

alright, the 3 Japanese verb groups are

group 1 (verbs ending in u)
like
話す [はなす]
and
書く [かく]

group 2 (verbs ending in iru or eru)
like
着る[きる]
and
見る[みる]

there are exceptions, like 入る[はいる], 知る [しる], etc. which actually belong in group 1

and group 3 (irregular verbs)

these are
する
and
来る[くる]

I'll link to a more complete list (and when I use a verb, I'll mention what group it is in)

these groups are important to identify the て form of the verbs

for 話す[はなす] the て form is 話して[はなして]

for 書く[かく] the て form is 書いて[かいて]

for 着る[きる] the て form is 着て[きて]

for 見る[みる] the て form is 見て

for する the て form is して

for 来る [くる] the て form is 来て[きて]

you might have noticed, 来て and 着て are the same in hiragana, so the groups aren't always useful for spoken japanese, but they are for written Japanese, when reading kanji, furigana are used sometimes, but when they aren't, knowing the groups can help you read the verbs at the very least

sometimes, even if two different words are written with the same hiragana, they have a different pitch accent, so chopsticks, and bridge are both はし, but the pitch accent is different (and the kanji), you can test this out in Google Translate, do take into consideration that the difference is subtle, so you may not notice it the first time

for some verbs, the ending would be... weird, if you did the "normal" thing of changing the last sound with て (like how 食べる changes to 食べて), for example, 飲む[のむ] would change to のて, but that's not the て form of 飲む, which is a group 1 verb, so you change it to 飲んで[のんで]

the た form, I mentioned earlier changes in the same way as the て form, so if you learn one, you pretty much learn both, the て form is the imperative mood, so if you say クッキー食べて[クッキーたべて] you're saying "eat the cookie(s)", which might be an order, or just a suggestion, the た form, is the past form, so クッキー食べた[クッキーたべた] is "ate the cookie(s)" (which could be "I ate the cookies", but it depends on the context), note that I omitted を before the verb, but in writing, you'd most likely see it

the た form can be used to say something along the lines of "have you ever done X?", for example, to say "have you ever eaten goat cheese?", you'd say ゴートチーズ食べたことある？[ゴートチーズたべたことある？], note that this is a question, but I use ? to convey that you would use sound it out as a question, rather than using か, because I would have to say/write ですか instead of just か to sound "normal", if I just use か it might seem like I'm being rude, you might hear anime characters speak like that, but normal Japanese people don't speak like that, or if they do, they only do it with really close people, here こと is like a "marker" that means that the previous sentence is the subject, so instead of "ate cheese have?" it's "regarding having eaten cheese, have you?" (this is kind of a literal translation, just to illustrate the grammar), ある means 'have', it's used only for concepts or things, not for living beings (actually, it can be used with plants, but we'll get to that later)

this sort of thing is common, and a useful way to ask someone if they have done something, another example with the verb 寝る[ねる], which is a group 2 verb, is 森で寝たことある？[もりでねたことある？], "have you ever slept in the forest?"

to say the opposite (that is, that you have NOT done something, you use the negative form of ある, which is ない), for example

Q: 森で寝たことある？[もりでねたことある？] "have you ever slept in the forest?"
A: いいえ、森で寝たことない[いええ、もりでねたことない] "no, I have never slept in the forest"

of course, you could also do it in the question

Q: 森で寝たことない？[もりでねたことない？] "you've never slept in the forest?"
A: ない "no"

you could also combine this to say something like "I had never done this until now"

for example

今までちゃんこ鍋食べたことなかった[いままでちゃんこなべたべたことなかった] "I had never eaten Chanko Nabe until now"

#JapaneseCulture
honorifics are small words you put after someone's names, they can sometimes be actual words, or sometimes be 'non-words"

for example, in 本田さん [ほんださん] "Mr. Honda"
さん is not exactly a word, but when translating, you refer to "Mr. Honda", not just "Honda"

but in 高木先輩 [たかぎせんぱい] "Senior X Takagi"
先輩 [せんぱい] actually means "Senior X", usually for organizations or schools, so a 3rd year student in school is the senior to a 1st year student, and an employee of a company is the senior of a recently hired employee, though in some contexts, so it is a word, but can be used like さん would be used, as an honorific

the most common ones are

さん used for formal speech
ちゃん used for kids, girls (like a girlriend), or childhood friends sometimes
くん used mostly for males of similar age, but can be used for female juniors
様 [さま] is very respecful, you mostly won't use this, but might see it used for gods, royalty or formalities in events
先生 [せんせい] used for professors, or professionals of some renown, common with physicians, and mangaka of high renown

there are others, but less common

you can put か at the end of a sentence to make it a question

it doesn't work for all sentences, but for a lot of basic ones it will work

if you think of 'indicative mood" sentences, it will work for most of them

for example

to turn "The weather is good today" into the question "is the weather good today?"

you can just add か at the end

今日はいい天気です [きょうはいいてんきです]

今日はいい天気ですか [きょうはいいてんきですか]

#JapaneseCulture

じゃんけん [janken] or 'rock-paper-scissors" can be very serious in Japan, it's even been used to decide which company would get to hold the auction of a collection of impressist paintings worth millions of dollars

you can put ね at the end of a sentence to say something like 'isn't it" or "right?"

for example, you can change

この焼き鳥は美味しいです [このやきとりはおいしいです] 'This Chicken is good/tasty!"

to

この焼き鳥は美味しいですね [このやきとりはおいしいですね] 'This chicken is good/tasty, right?"

you would drop the は and the です in an informal setting, so you'd say

この焼き鳥美味しいね [このやきとりおいしい] 'this chicken's good/tasty, right?

焼き鳥 yakitori is skewered chicken

to ask someone about their age you say

何歳ですか [なんさいですか] 'how old [are you]?"

in a more informal setting, it would be more like

何歳？ [なんさい?] 'how old [are you]?"

it's rather uncommon to ask this, unless people are relatively close in age (they don't distinctively look older than the other), but in a bar or social event where people are consuming alcohol, it's likely to happen, because people are supposed to show respect to their elders, even in informal situations, this might be more of a Societal thing in Asian countries, not just in Japan

in a formal setting, or when talking to someone with more renown, you might ask 年はいくつですか [としはいくつですか] 'how old are you?" which is more formal