If you are an Office 365 global administrator, you can set up Skype for Business to play its default voicemail greeting in another language. The default system greeting is something like, "Please leave a message for John Smith. After the tone, please record your message. When you finish recording, hang up, or press the pound key for more options."
First, read this important info:
The languages that are available to you are determined by the location of your organization. For example, if your organization is located in the United States, you can set the default language to English or Spanish. If your organization is located in Canada, you can choose between English and French. For a list of supported languages, see Languages for voicemail greetings and messages.
There's no way to change the system language for only one person in your organization. You can only change the greeting language for everyone on your organization.
Note: Users can change their own greeting language through their settings after they sign in.
Do you want to record your outgoing voicemail message? See Change your voicemail greeting.