I thought I'd throw in random lessons in japanese. I have questions no one around me can awnser, and Ill post things I've always wondered and learned. Small things that make a lot of sense after you learn it. For now I'll work with verbs and at the bottem I'll ask a question. Now for intro.
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nihongo ga daisuki desu yo! watashi wa Randy desu. Watashi no adana wa Rakke desu. jyuunanasai desu. rokugatsu watashi wa nihon ni ikimashita. nihon no koukou ni ikimashita. Hosuto famari(katakanade shirimasen, gomenne!) wa totemo yashikatta desu yo. ikkagetsugurai nihon ni imashita. ichinengurai watashi ha nihongo wo benkyoushimashita kedo,watashi wa takusan obemashita. Dakara, watashi wa nihongode chotto hanasemasu. Demo, tokidoki doushitoka, kakokeitoka,kanjitoka muzukashi desu yo ne! nihon ni eigo no senei ni naritaidesuyo ^__^
Yoroshikuonegaishimasu ^__^
---English---
I love Japanese! I am Randy. My nickname is Rakke. I am 17 years old. In June I went to Japan. I went to a Japanese High school. My host family (in katakana I don’t, sorry) was very nice. For about 1 month I was in Japan. for about 1 year I have studied Japanese but I have remembered a lot. so I can talk a little in Japanese. but sometimes things such as verbs, past tense, and kanji can be difficult right. I want to become a English teacher in japan. Nice to meet you.
CAN DO/ CAN NOT DO(IS ABLE TO/IS NOT ABLE TO)
I'll throw some random Japanese help in when I can. for now, going to show how to change verbs to Can do or cant do.
Group 1-----
Kaimasu(kau) Buy-
Machimasu(Matsu) Wait
Shirimasu(Shiru) Know
Kakimasu(kaku) Write
Oyogimasu(oyogu) Swim
Hanashimasu(hanasu) Speak, Talk
Shinimasu(shinu) Die
Yomimasu(yomu) Read
Asobimasu(asobu) Play
Group 2-----
Tabemasu(taberu)
Mimasu(Miru)
Irregular-----
Kimasu(kuru)
Shimasu(suru)

these are examples of each verb. 1st group is I,chi,ri,ki,gi,shi,ni,mi,bi. With there all you have to do is change the last I to E. This will change them into group 2(these are not the official group names but this is just to show you)

Kaemasu(kaeru) Can Buy-
Matemasu(Materu) Can Wait
Shiremasu(Shireru) Can Know
Kakemasu(kakeru) Can Write
Oyogemasu(oyogeru) Can Swim
Hanasemasu(hanaseru) Can Speak, Talk
Shinemasu(shineru) Can Die
Yomemasu(yomeru) Can Read
Asobemasu(asoberu) Can Play

The ones in ( ) these are casual form. And because they are group 2, ru is simply added. Ru is the same as Masu, but casual. As masu is more formal. you will notice Chi and Shi do not become Che and She. this is because Chi is in Ta-to of hiragana(ta chi tsu te to) and shi is in sa-so(sa shi su se so) it takes the e character in that batch. Chi-Te, Shi-Se.

Now for group 2. This end in e of I, there are some group 1s that look like group 2 but are not. Get tricky, but you'll get use to it.
These are one of the easier. Their base does not change. Tabemasu(taberu)-Tabe is kept. Mimasu(Miru) Mi is kept. All you add to make it can is- remasu(reru).

Taberemasu(tabereru) Can eat
But Mimasu is different when it comes to this. Mimasu becomes
Miemasu(mieru) Can see
another one of these that are different is
Kikimasu(kiku) Hear
This becomes
Kikoemasu(kikoeru) can hear

Now Irregulars-
Kimasu(kuru) Becomes Kuremasu(kureru) or Koremasu(koreru)
Shimasu(suru) becomes Suremasu(sureru)

now for verb ending.
Can do(is able to) Same as above ends in masu or ru (casual)
Could do(was able to) add Mashita or ta (casual)
Can't do(is not able to) add Masen or nai (casual)
Couldn't do(wasn't able to) Add Masendeshita or nakatta (casual)

watashi wa eigo de hanasemasen
watashi wa eigo de hanasenai(casual)
I can’t speak in English

Thought with casual negative, you can add desu to raise the politeness.
watashi wa tobenai desu.
I can't fly.

for structure:
noun--wa--Noun,item,etc--wo--"Can/can't do" verb

Subject--wa(states the subject of the sentence: When written in hiragana it is ha but pronounced wa)--Noun, item, etc.(the item the first noun will interact with)--wo(particle before verb, not always wo, depends on what you want to say, it depends on the verb too.)--Verb, show how the 2 nouns are connected in action--

but if you just want to say something like
"I can eat" as opposed to "I can eat food"
watashi wa taberemasu.
The wa is stating the subject so you don’t need the wo, because, there is no 2nd noun and such.

you WOULD NOT say
watashi wo tabereru
that is wrong, unless you're crazy.
If the subject of the sentence is known before hand, you do not need to repeat it. so in this case the translation is
"I can eat me."
XD and I hope you can't

If you didn't understand anything, don't hesitate and hit me then ask XD
I'm a first year in japanese, but I've been memorizing my textbooks so I know most of what I talk about. I've been to Japan and went to school for a month(2nd year high school student, I'm really a senior in High school) But if you are better, don't totally kill me and politley correct it XD
Just don't correct my english, I know I suck at that XD Hope this helps, later all add more on things like this.

Now for my question:
Does someone know the reason and the for verbs like
Wakanai
It means the same as wakaranai(dont understand) or so ive been told.
but i dont know how to set up other verbs like this. I'll be back later to do more verb and whatnot. ^_^

haha its almost the same wif my text book omg x(
but mine is more is more systematic no offence =(

Quite an old post, but I accidently found this, while looking for info on kureru/koreru...

Here, the description of the potential form of suru is WRONG, according to me (and according to "Japanese, Verbs&Essentials of Grammar" by Rita L. Lampkin).

The potential form of the irregular verb suru is dekiru (dekimasu).

hmmmmm