Run-on sentence

[Job]

Please edit this run-on sentence:

It is a contradiction that a native English speaker who could handle their mother tongue skillfully would not like to use rude English hence ESL students lost the chance to learn what is rude/improper talking in English while the native speaker hopes what the students talk keeps the virtue of proper English.

[twostep]

Please edit this run-on sentence:

It is a contradiction that a native English speaker who could handle their mother tongue skillfully would not like to use rude English hence ESL students lost the chance to learn what is rude/improper talking in English while the native speaker hopes what the students talk keeps the virtue of proper English.

I have been starring at this monster of a sentence for some time. What are you trying to say? That native teachers hope to keep ESL students from using improper language?

[Casiopea]

Welcome, Job.

It would help if you could show us how you would make the sentence better. What are your thought?