Yes they can!
There are 3 options that you can choose which will determine the written language of your emails.
Default (English) -- By default, emails are written in English.
Prospect's Native Language -- This is a great option if you have multiple countries in your target audience filters. The agent will look at the prospect's location and write the email in the official language of the country/region they are located in.
France = French
United Kingdom = English
Sweden = Swedish
Etc.
Choose A Language -- This will allow you to choose 1 language to override the default language with. Meaning all emails will be generated in ONLY the language you choose.