I'm very happy these days 'cause I'm back to study ging German and sometimes take a look in iItalian and hiragana (a jJapanese alphabet), but gGerman is my focus.

In English, languages are considered proper pronouns and need to be capitalized.

Before that, I just sleept all day or played Assassins Odyssey.

The phrase "Before that" implies that these actions took place in the past, so you need the past tense here.

I'm trying to learn gGerman on my own since I don't have money.

I have spent hours studying like listening, reading, and speaking.

Using a comma at the end of a list (it's called an Oxford comma) is debated in English, but it's useful in order to separate different ideas or items in the list. I hope that makes sense!

My sleep hours are twisted,ing schedule is messed up. I'm bBrazilian, so iI love coffee - we planthave a lot of coffee plants - so I drink 2 (two) or 3 (three) cups of coffe oe in an afternoon.

Brazilian is a nationality, so it's a proper noun that needs to be capitalized.

And just so you know, numbers under 10 in English are spelled out in formal writing. In informal writing, it doesn't really matter.

But iI think iI'm immune to "cafeína",feine 'cause iI've been drinking this since i hI was a kid.

"I" is a proper pronoun is English and needs to be capitalized regardless or where it is in the sentence.

We say "I've been drinking" or "I have been driving" because this is an action that started in the past and continues in the present.

I have to fix that, and sleep right.

Today i eI ate bread and cuzido.

Or if you meant to say this in the present tense, you can say "Today I'm eating bread and cuzido".

I'm eating a lot and because of that, I gained some weight.

I'm very happy these days 'cause I'm back to study ging German and sometimes takeing a look in iat Italian and hHiragana (a jJapanese alphabet), but gGerman is my focus.

Names of languages are considered proper nouns and should be capitalized. I'm guessing Hiragana is a proper noun, as well.

Before that, I was just sleeping all day or playing Assassins Odyssey.

I'm trying to learn gGerman on my own since I don't have any money.

"I don't have money" is ok, but adding "any" makes it more natural. Also, "I don't have money" can mean "I'm not wealthy".

I have spent hours studying like- listening, reading and speaking, for instance.

Or you could say, "I have spent hours studying doing things like listening, reading, and speaking."

My sleep hours are twisted,: I'm bBrazilian, so iI love coffee - we plant a lot- soand I drink 2 (two) or 3 (three) cups of coffe oe in an afternoon.

If you want to make this into a single sentence, you need either a colon or semi-colon connecting the two thoughts. Otherwise, just use a period to make two sentences. I used a colon because I think you're saying your sleep hours are twisted as a consequence of your afternoon coffee consumption. I personally would say "turned around" rather than "twisted" in this instance.

But iI think iI'm immune to "cafeína", 'because iI've been drinking this ever since i hI was a kid.

The abbreviations "I'm" and "I've" can be used at virtually any level of formality, but abbreviating "because" to "'cause" makes the writing very informal - which actually may be what you want here :-).

Today iI eat bread and cuzido.

I don't know what "cuzido" is, but I assume it's a Portuguese food?

I'm eating a lot and because of that I've gained some weight.