trilingually

/traɪˈlɪŋɡwəli/
adverb
  1. In a way that involves or uses three languages.
    • She grew up speaking trilingually, switching between her mother's tongue, her father's language, and the local dialect.
    • The website is designed trilingually to serve users in English, Spanish, and Portuguese.
    • The conference was conducted trilingually, with simultaneous translation in three languages.