Write about a motivation to learn a language (motivation is both uncountable and countable, so when you use this word, if you want to talk about a particular motivation, you should use "a" or "the", but when you just want to describe a general motivation, you can use it without any article)

Say Theory is easy so but when put into practice, it practice is difficult.

Sometimes I feel disoriented and wanted to give up. (there should be a subject in each sentence)

Sometimes I wondering, wonder why (Do not put a comma between "wonder" and "why") people can learn so many languages at a time. ?

And themselves is only learning a language is English which also saw difficult.  Meanwhile I feel difficult to learn only one language.

Reasonable It is because myself I am too lazy and the my motivation is not strong enough or myself I have not identified themselves effective learning methods.

Then what is wanted to study but ultimately đi not learn anything (I really do not understand this, does this mean: "I wanted to study something but finally I couldn't study anything"?).

it made me quickly discouraged quickly.

I wish someone could learn with me, I will have more motivation to learn together.

Because as studying alone (You just need either "studying alone" or "studying without anyone practicing"), I will very quickly soon forget and quickly get bored.

I didn't know you meant yourself until I read the last sentence. You need the agreement among sentences. If you mean about someone else, you should use "you" or other pronouns. But if you mean to talk about yourself, you should use "I" until the end.