Learn hiragana/katakana if you still haven't. Then you wouldn't make mistakes like
seeing suki as an i-adjective...
miruku ga sukkunai na
miruku ga suki ja nai
(I) don't like milk
miruku wa yokunai shinjiru
信じる(shinjiru) is a verb that means "to believe" or "have faith in"
I was practicing grammar awhile back with it so I have an example sentence:
日本人は生きる目的が天皇に仕えることだと信じた。 (nihonjin ha ikiru mokuteki
ga tenou ni tsukaeru koto da to shinjita) Which means "Japanese believed
the purpose of life was to serve the emperor." That's how 信じる(shinjiru) is
miruku ga yokunai to omou
(I) think milk isn't good.
kyou wa koukou e ikanai
Kyou ha koukou e ikanai
(I) won't go to high school today.
You may want to consider the use of 学校(gakkou) instead. 高校(koukou) isn't wrong
but I'm just thinking of the scenario that you're probably thinking of. 高校(koukou)
just seems highly specific for most situations in my opinion. When I was a high school
student I wouldn't ever say "I'm not going to high school tomorrow"... I would always
just say "I'm not going to school tomorrow"
You did your contrasting with は(wa) wrong in the next two. They are both negative.
what exactly are you trying to contrast? You should try having one in the negative
and one in the positive. I'm going to put them into 1 sentence.
tamanegi wa taberu koto ga sukkunai na. soshite, tamago wa taberu koto ga sukkunai na
You tried to say "I don't like to eat onions. And then, I don't like to eat eggs". That doesn't even
really make much sense in English to be honest. Let's try doing it this way:
tamanegi ha taberu koto ga suki ja nai kedo, tamago ha taberu koto ga suki desu.
I don't like to eat onions but, I like to eat eggs.
Here you are contrasting eggs with onions in a way that makes sense. Before you were
contrasting them in a way that didn't make much sense.
kono bideo geimu ga sukkunai na
kono terebi ge-mu ga suki ja nai.
(I) don't like this video game.
furansu ga hanasanai
furansugo ga hanasenai
hanasenai is the negative-potential of hanasu. Which I believe is what you really wanted to say. Also don't forget to append the -go to the name of the country to specify that you're talking about the language.
furansugo o hanasai
isn't incorrect but it means "I won't" or "I don't speak french"... Nothing about your ability. Which is something I think you didn't intend.
One last note: when I see -na I think either "negative-imperative" or "kansai-ben of ne" either of which would be wrong in all of the cases you used. I think you meant なあ(naa). Please do a long a sound when doing that
I realize this is a slight necro-post however the rules state that it's ok to necro-post if what you have to say contributes to the topic. I believe this contributes. So don't jump down my throat lol -_-