Not looking to get into an argument here, but I don’t think it’s surprising to conflate ‘politeness’ and ‘formality’, especially in the case of Japanese. I mean, I’ve never lived in Japan, so I can’t confirm this, but I feel as though there’s a whole set of protocols surrounding what to do in order to be polite in formal situations (especially when it comes to business). Formality is technically about following rules, while politeness is about being respectful, but if being polite requires following rules, then politeness and formality feel like almost the same thing. That’s my personal justification for using ‘polite’ and ‘formal’ almost interchangeably, even though I’d definitely say ‘that isn’t polite’ when commenting on a rude action, and not ‘that isn’t formal’, which would sound ridiculous.
I’m aware that technically speaking, even the plain forms aren’t universally casual: they can be used for writing, for instance, like in essays. However, well… I just don’t feel like the line between ‘formal’ and ‘polite’ is clearly drawn in Japanese? (Point me towards resources where such a line is defined, if you wish, because I haven’t come across it yet.) My personal way of seeing those forms is (with adjectives in order of decreasing suitability/preference):
だろう – plain/casual
でしょう – polite/formal, mainly for speech
であろう – formal/polite, mainly for writing
I definitely agree that であろう is more ‘formal’ than it is ‘polite’, because it seems to exist for the sake of conforming to a particular style of written Japanese, as opposed to being used to show respect. Similarly, でしょう is more ‘polite’ than it is ‘formal’, because the です・ます forms convey respect.
That’s just my two cents. I’m not really sure what I’m getting at, ultimately, since it seems I agree with you on most of your points… perhaps my point is that I don’t think it’s a serious issue if resources conflate the two, particularly since polite language tends to be used in formal situations, and vice versa? 丁寧語 definitely translates as ‘polite language’ and not ‘formal language’, but I’ve never seen a textbook define ‘formal’ language separately and state that it would be improper to use it in a ‘polite’ situation. Also, at the beginner level, like you said, the forms typically reserved for writing (sometimes called the である体, though I think they also include the 連用形/masu-stem being used at the end of clauses like a て-form) don’t usually come up, so there’s little risk of confusion.
My understanding, though I’ve never actually gone hunting for Japanese commentary on the structure, is that it’s acceptable. I’m pretty sure I’ve heard 「〜ないといけないから!」come up in an anime at least once, and from the mouth of a character who wasn’t presented as unintelligent or anything like that. Also, I just did a quick Google search, and 「ないとならない 」 did get used in The God of High School, which is a fairly recent anime.
However… yes, it also came up as ‘not used’ or ‘strange’ according to a few people here and there. In any case, I personally never use ないと [いけない・ならない] to begin with, so I’m not sure what to think. ないといけない definitely feels more natural since ないと is casual and いけない tends to refer to a personal sense of obligation, especially due to expecting non-action to have an unpleasant consequence on a personal level, so they feel like they fit together better. ならない is more for ‘obvious’ obligations or social expectations. However, I still think なくては and なければ are the most common and useful (they even get turned into なくちゃ and なきゃ in casual conversation, so you don’t need to learn extra expressions to understand!), with ねば coming in at the higher levels (though I really don’t think anyone says that anymore, even if it appears in writing and literature).
Ultimately though, I’m inclined to agree with your other points. They sound pretty bad (even if I haven’t seen the は and が page).
I’d say focus more on #2. I started avoiding Tae Kim’s site because 1. I heard he was sometimes wrong 2. I found it too grammar-focused and I disliked the layout. However, he’s probably not always wrong, and there are a lot of examples sentences on his site, which could be helpful. My personal favourite English resource (in text form, anyway) is Maggie Sensei’s website. Some people hate the colour scheme – maybe I’m immune to it because I’m slightly colour-deficient, so I see some colours less distinctly –, but I think the content is great, with lots of examples, simple explanations (the lady writing it is Japanese, so her English isn’t perfect, but that also means she tends to simplify things, which is good for learners) and romaji transcriptions. I mean, you shouldn’t rely on romaji too much, and you should definitely try to read whatever you can before looking at the transcription, but it’s good for beginners who haven’t got used to kana yet. Some other people like Cure Dolly’s videos. I don’t like the formatting and the mechanical android voice, and I think some of her ideas are way too controversial/far-fetched, but the content seems fairly good, so I’ll give her some credit.
Beyond these ‘Japanese teaching’ sites, you should probably also look at sites that are a little more grammar-focused. Wasabi Japan is one. You might also want to look up specific topics that you need to strengthen, like an ‘introduction to Japanese verb conjugation’. Wikiversity has good pages on that which you may want to look up:
https://en.wikiversity.org/wiki/Beginner_Japanese/Godan_Verbs
https://en.wikiversity.org/wiki/Beginner_Japanese/Ichidan_Verbs
I used these to help me along when I first started, even though my textbook actually already covered the topic. They gave me another perspective on verb stems, especially since my textbook used different terminology. The main difficulties in verb conjugation at the beginner level are
- Forming the masu form
- Forming the ta form
- Forming the te form (though these are very similar to the ta form)
Some of the intermediate-level difficulties with verbs are
- Forming the causative, passive, potential and volitional forms
- Using the masu-stem instead of the te-form (not strictly necessary to reach higher levels, but good to know that it exists, along with the nuances)
- Realising that ている isn’t just used to mean ‘to be doing/singing/eating/flying etc’, and then learning when to use it instead of the simple present tense (aka dictionary/plain form) and the past tense (aka plain/dictionary past tense)
That aside, you may sometimes want to just Google stuff like ‘[verb] conjugation’ and see what comes up. If Bunpro doesn’t label what all the different forms are, then you should probably use other reference sources from time to time, because most online conjugators label everything. That aside, if there’s a structure you’re not sure about, it’s sometimes more helpful to just Google ‘[structure] grammar’ and to click on stuff like JLPT websites.
OK, I think that’s enough advice for now. Hope you don’t feel overloaded by all that. All the best!