Is this passage grammatically correct?

When Japanse people talk to people order than them or they respect, they use the three speech levels:honorific, polite and modest. In business talks, they use them according to the situation. Most Japanese people think that there are no such speech levels in the English language, but English speakers use the subjunctive mood instead as in "Perhaps you could pass me the salt." for "Pass me the salt." Also the choice of words in order to avoid explicit expressions has the same effect. For example, "His mother passed away last night." would be preferable to "His mother died last night." Some Japanese teachers of English simplify rules which make English sound polite into one: The longer the sentence is, the more polite it sounds.

>"When Japanse people talk to people older than them or they respect, they use three levels of speech: honorific, polite, and modest."
>"In business discourse, they are used according to the situation."
>"Most Japanese people think that there are no such speech levels in the English language, but English speakers use the subjunctive mood instead, for example, "Perhaps you could pass me the salt." in place of "Pass me the salt."
>"Also the choice of words in order to avoid direct expression has the same effect."
>"For example, "His mother passed away last night." would be preferable to "His mother died last night."
>"Some Japanese teachers of English summarize the guidelines of politeness into a single rule: "The longer a sentence is, the more polite it sounds."

I changed some vocabulary as well to make more sense