Japanese conversations.

konnichiwa!

I don't get why some of the Japanese on the lessons say something about a casual form and a plain form? It all so said to only use with friends and family? Is it saying to only write to family and friends and to only say these sentences to them in the Japanese language?

Here is an example of what I don't under stand/ 今起きたばかりだ。/ ばかりだ is the plain form. Only use this with family and friends.

こんにちは (Konnichiwa) ElijahG15,

Thank you for your question! 

That's correct: the plain form is casual and should only be used when speaking to friends or family.

In Japanese, it's important to change the way you speak depending on who you are talking to in order to show respect. When speaking to people you don't know well, you should use polite language. When speaking to strangers, aquaintainces, neighbors, work colleagues, etc. you should use polite forms. When speaking to people you know very well; however, you can use plain forms, which are casual. 

When used at the end of sentences, the plain form makes a sentence casual overall. Because of this, you should only use  plain forms to speak to people who you know very well. 

The exception to this is when a plain form is used as part of a grammar construction. In this case, it's not casual: it's just a building block used to create that grammar construction. When plain forms are used in this way, though, they won't appear at the end of a sentence, so you'll know they're not casual in this context. 

So the plain form is casual, yes, but only when it comes at the END of a sentence. 

The sentence 今起きたばかりだ (Ima okita bakari da) “I just got up” is a casual sentence since it ends in だ (da) “is": the plain form of です (desu) “is.” Since the plain form is used to end the sentence here, it makes the sentence casual overall. Because of this, this sentence would only be used when speaking to friends or family.

When speaking to strangers, aquaintances, work colleagues, etc. you would need to use the polite sentence 今起きたばかりです (Ima okita bakari desu) “I just got up." This ends in the polite form です (desu) “is,” making it a polite sentence overall. 

I hope this makes sense!

Here's a link to the lesson on the plain form if you'd like to learn more. It compares the plain and polite forms, so it's a great one to look at if you're finding this concept a little tricky! 

https://app.rocketlanguages.com/members/products/5/lesson/5172

勉強を頑張ってください！ (Benykō o ganbatte kudasai!)