回複：

Hi
Based on your information, the Chinese language skill is not required for your job, but only facilitates communication within the company. Thus, it would be very difficult to justify the Chinese language skill requirement.
It also depends on what type of LC you are applying. If you apply through regular, the state labor department would review your ad before it goes out and would probably delete it if they think it improper, so it does not hurt to have the language skill requirement in there first; if you apply through RIR and the application gets rejected for the language after the recruiting effort, it would waste you lot of time and money, so probably you would not want to add the language skill requirement.