行こう
〜よう is for ichidan, not for godan 
行きましょう would be the polite 〜ます ended form and alternative to 行こう as @yamitenshi pointed out.
I think it might be a good idea to have a look at some verb conjugation videos, for instance from Cure Dolly or other teachers 
.
That and/or group 1 and group 2 verbs. Those terms always confused the heck out of me. Godan and Ichidan make so much more sense.
I just remember the following common exceptions and that takes care of like 99% of cases:
Godan verbs
はいる
入る
かぎる
限る
はしる
走る
きる
切る
いる
要る
しゃべる
喋る
かえる
帰る
しる
知る
nah they straight up never mentioned it
What are you using to study? Group 1/2 and う/る are the two main ways of describing it outside of Godan/Ichidan from what I’ve seen, although that may be falling out of favor.
BTW, the Tofugu page has a pretty good write up on all this:
If we are looking for words that nominalize 食べ, there is at least one: 三角食べ
No, it’s not the most common word in the world, but it’s not that exceptional either. They have a wikipedia page for it and all.
Couldn’t come up with any other word, though 
（well, of course there is ばっかり食べ, but it’s clearly related to 三角食べ, so）
ながら食べ and 遊び食べ~
But yeah its hella rare compare to ~食い
Very. Why would you use a name that is not the slightest bit descriptive of what verbs go in which group? TextFugu used to use the group 1 and 2 style. So did Nakama, except they applied it the other way around. I’m pretty sure, anyway - I can never keep them straight regardless.
To continue the history lesson, all 五段 verbs used to be 四段 instead - the ～お stem is a comparatively recent innovation. Meanwhile, the 一段 verbs used to be split into 一段 and 二段, but the extra stem for 二段 was removed - the only 二段-like verb still remaining is 得る, which can be read as both うる and える.
I find that implausible - are you sure you weren’t just asleep that day? 
If you don’t teach the general conjugation rules by verb group, then you’d need to teach them on a case-by-case basis, and that just feels needlessly complicated.
(WaniKani uses “ichidan” and “godan”, so keep an eye on the “word type” field next time you’re reviewing.)
And if you use Yomichan (I can wholeheartedly recommend it if you don’t, by the way) some dictionaries like JMdict will add a tag with v1 (for ichidan), v5 (for godan) or v5r (godan verb ending in -ru) to help you know how to conjugate verbs.
Monolingual dictionaries also tend to list it - possibly important note there: you might see a distinction between 下一段 and 上一段. That just refers to whether the verb ends in -iru (for 上一段) or -eru (for 下一段).
I imagine the rational is similar to other things that people like Cure Dolly will claim are being “hidden from you” (evil laugh).
Basically, to an absolute beginner, almost any names for these categories will just be meaningless labels. Even if you tell them there’s a reason for the label, it will take considerable explanation time for it to “click” with a complete beginner as to why ichidan and godan make sense (u and ru also have problems in that they are imprecise names).
So, yeah, I think that’s why people choose to go with some of these seemingly “less helpful” names or explanations, because one goal is not to overload or intimidate beginners.
I get that there’s a strong reaction among hardcore studiers to that kind of resource, but if everyone was hardcore, sure, it wouldn’t be as much of a concern.
Private tutor that makes courses I can follow. When I’m done if I haven’t learned too much I’ll just post all my questions here until I’m intermediate 
No 
So maybe the appropriate question is “what is your tutor using to make lessons”. Hopefully not just winging it entirely.
We talked about it a little bit in my linguistics class only to say that 食べ was not a sort of prefix, which confused everyone who spoke/was learning Japanese, but she moved on and we never really got an explanation, so I’m going to guess it’s either debated or she just didn’t want to spend class time on it 
What does this mean?
Winging it… Doing things without a bigger plan. Making their own plans one at a time without using a curriculum.
He has a doctor’s degree in japanese, which admitedly isn’t worth much if the person can’t teach, but the lessons are all right
Hi I’m looking for some advices here please. 
If I’m trying to watch a Japanese drama same episode twice to practice my Japanese.
Should I watch it without subtitle then watch it again with subtitle to check my understanding, or the other way around?
I’d say without then with. If you watch with before, then you’ll be expecting things to be a certain way and overestimate your comprehension I think
I second this. I’ve done something similar with やがて君になる, trying both reading a chapter in Japanese first and then checking my understanding with the English version, and reading English first and then reading the Japanese knowing the basic gist of what it should mean, and the former forces me to focus on the Japanese and what it means. Then when something doesn’t quite match up in the English version I can go back to the Japanese and see why it might mean that - whereas if I go from English to Japanese I’m inclined to just go “oh it means X”.
If I’m not wrong, it’s the result of a sound change: う is the original helper verb, and it was typically attached to the 未然形 (-あ stem). Many -au sounds turned into -ou sounds, and that’s how we got an -お stem.
It might also be that different terms are used? I’ve seen ‘-ru verbs’ and ‘-u verbs’ mentioned by resources for English speakers. (I agree that I prefer the systemised approach though, regardless of terminology.)