I really want improve my skills about ein the English language but currently I need to finish some projects related withto my previous workjob.

(1) The phrase is "skills in (something)".
(2) We typically use the article "the" before the phrase "X language", since "language" refers to a specific language. However, you don't need it if you just write "English".
(3) "English" is the name of a language, so it's a proper noun and always capitalised.
(4) Alternatively: "I really want to improve my English skills".
(5) The phrase is "related to (something)".

Sometimes I feel like I am stangnant, because I would like to speak more fluently, however I don't get downiscouraged.

(1) I think the sentence will flow more naturally without the first comma.
(2) The phrase is "would like to (do something)". Alternatively: "because I want to speak more fluently".
(3) The phrase you're looking for is "get discouraged".

Perhaps it will take more time but fineventually I will become an eEnglish speaker as bettergood as a native.

(1) For events that will happen after a long time (but haven't happened yet), we use "eventually" and not "finally".
(2) The phrase is "as good as (something)".
(3) You need an article like "a" before "native". You need one before all nouns most of the time.
(4) Alternatively, but this is more advanced: "I will become as good an English speaker as a native." The structure here is "as good a (something) as (something)".

I really want to improve my skills about english language skills but currently I need to finish some projects related withto my previous work.

Sometimes I feel like I am stangnant, because I wshould be speaking more fluently, however I dwon'’t get down.

Perhaps it will take more time but fineventually I will become an eEnglish speaker, as betterlmost as good as a native.