I think young people are sometimes disrespectful in their speech.

我认为年轻人有时说话失礼。

It's rude to point your fingers at people.

用手指指人是很失礼的。

Being late is an unforgivable sin round here.

迟到在这里是一原谅的失礼行为。

It is ungracious of me not to acknowledge your help.

大力帮助而我尚谢意，十分失礼。