The salaryman cannot stop.

There have has been a well-known song in Japan since approximately 30 years ago. "A salaryman is a very easy job," A The lyrics of the song start as such like this (In Japanese,"サラリーマンは気楽な稼業ときたもんだ") I wonder that if you may might know what the Japanese word "salaryman" (サラリーマン) means in English. It means "employee, especialy a white colour collared worker." 

Sometimes, there are people who think of a job like the song. They are satisfied for withtheir work and have no interest in promoting others. Although It's very happy beneficialfor them, I suppose, their existence threatens inferiores inferiors. If they keep themselvestheir position, inferiores inferiors will not be promoted. In order to avoid the thiscircumstance, the employer must lay off the position-keeper the ones who have their positions. It's unfortunate for all of them. 

Finally, a salaryman isn't a very easy job. We make a lot of efforts to keep working. In my opinion, It's happiness extends more further than that.

Hello Masa. I would be delighted to assist you once again.

1) The title "Salaryman cannot stop," is missing an article. In certain contexts, the rendering "A salaryman cannot be stopped" is possible. In this case, perhaps "The salray man cannot stop" will suffice.  

2) The phrase "have been" is flawed, because it is modifying a singular subject, namely, "a well known song," and so the plural "have" must be changed into the singular "has." 

3) "Japan" is a proper noun, thus it should begin with a capital "J."

4) "Very easy job," should be "a very easy job." Whenever an adejective is going to be used to describe a noun, the case is generally that the article "a" is prefixed to the adjective. Example a) "a very easy job," b) "an easy job," c) "a fast car," d) "afoolish supposition," e) "a wise conjecture," f) "a beautiful girl."

5)  The phrase "a lyrics," should be "the lyrics," because the lyrics of reference are specific. 

6) The phrase "as such" is very understandable, but it is not the common choice of words in this context. I recommend "like this" instead. 

7) "That" is not necessary in the phrase, "I wonder that if." 

8) The word "may" here can probably stand as it is, but personally I would have said"might."

9) The phrase, "if you may know, the word 'salaryman' is Japanese-English" is flawed in view of the proceeding choice of words. I recommend, "I wonder if you might know what the word サラリーマン (salaryman) means in English."

10) The phrase, "employee, especialy white colour worker" is probably wrong. "a"must be prefixed to "white." "White colour worker," comes closest to meaning a working person whose complexion or skin colour is light. I assume you meant,"especially a white collared worker." This means a working person who wears white collars. 

11) Although the phrase, "I suppose, a existance of them threat inferiores" is flawed, the thought still was apparently rather eloquent. Modifying it and maintaining the same words makes it sound relatively eloquent. The correction is "I suppose that their existence threatens inferiors." The word "inferior" is not wrong at all, but it can have a negative connotation under certain circumstances. The way in which you used the word did not have a negative connotation, therefore it may stand  as it is. I have noticed that there is a widespread belief that the word "inferior" is always disparaging.

This is false by definition of what the word means. I cannot find anything wrong with this choice of word. The offense merely lies in the mind of the person who hears it, because in and of itself, it simply means "a lower degree or rank," and there is nothing offensive about this definition, hence the acceptability of this choice of word from my perspective. Alternatively, you could have said, "I suppose their existence threatens those of a lower status," but the former word "inferior" already covered this well. 

12)  The word "finally," is justified, because it appears evident that you are closing out this note, therefore, it may stand as it is. 

13) In place of "In my opinion, It's happy more than that," I recommend, "In my opinion, It's happiness extends further than that."

In my opinion Masa, there is noticeable improvement. It is good that you are making progress. I am glad to help further your progress whenever you so desire.