what is the difference? are these three grammar structures different? or could they be used interchangeably? 飲まないといけません。 飲まなければなりません。 飲まなければいけません。 Thanks in advance.

accents hello, i was wondering if some of the english native speakers here could help me identify the accents used in the video linked below. it's from an older movie starring marylin monroe. thanks in advance. https://www.youtube.com/watch?v=viUT9Alc1yo

is this rude? Is it rude not to use "です" after a noun? For example, "これは私の部屋。" instead of これは私の部屋です。 Is it okay to say this to strangers? thanks in advance

being polite in japanese こんにちは, the other day my friend came across some kind of J-drama where this particular person speaks to everyone in casual Japanese, even strangers. She would say stuff like "いいよ。", 小さいサイズある？", and so on. Why does this person do this and is this normal in Japan? Thanks in advance.

what is the difference? What is the difference between あって and ありまして? They're both te forms but could they be used interchangeably? Thanks in advance.

2 questions Hi, I have two questions regarding Japanese sentences: 1) How would you say this sentence "ここにならあるかもな。" in a polite way? 2) Is this sentence "だれもいなさそうだな。" grammatically correct and natural? How would you say it in a polite way? Thanks in advance.

Does this conversation sound natural and polite? "それに、どこでそれを学びましたか？" "お父さんに教えてもらったのです。まだうまく使えないですけどね。" Thanks in advance.

pronunciation question Why does the character (the black haired one) tend to stress the SU part in "desu" and "masu"? The video is really short: https://www.youtube.com/watch?v=PLepNczfAc4 Thanks in advance.

deSU maSU Hi, I've heard a lot of people pronounce "desu" and "masu" as "deSU" and "maSU" instead of "des" and "mas". (both male and female) Why is that? Why do people say that? There's this one person who pronounces them this way all the time. What's the difference? Thanks in advance.