[Grammar] about preposition in relative pronoun clause

[Yoshio]

Will you tell me whether the below sentence is correct or not?

It is good manners to speak in the language that one is spoken to.

I suppose "that one is spoken to" is a relative pronoun clause, in which case, I guess the preposition "in" at the end(or after "spoken to").
Am I correct or not?

I would appreciate your help.

 

[Kondorosi]

Will you tell me whether the below sentence is correct or not?

It is good manners to speak in the language that one is spoken to.

I suppose "that one is spoken to" is a relative [STRIKE]pronoun[/STRIKE] clause, in which case, I guess the preposition "in" at the end(or after "spoken to").
Am I correct or not?

I would appreciate your help.

Yes, it is a reduced relative clause. The preposition is stranded and attached to 'one'