Parallels Desktop for Mac 20 supports the following languages: English, French, German, Italian, Spanish, Czech, Polish, Portuguese (Brazil), Japanese, Korean, Simplified Chinese, and Traditional Chinese.
By default, Parallels Desktop displays its menus in the same language your Mac's interface is set to, provided it is one of the languages listed above.
You can change the language by doing the following:
Quit Parallels Desktop.
Choose Apple menu > System Settings > General > Language & Region.
Scroll to the bottom and find the section called Applications.
Under Parallels Desktop, use the drop-down menu to select one of the interface languages that Parallels Desktop supports.