According to the Microsoft Download Center , the English Language Interface Pack (64-bit) requires:
Your Office 2016 is not activated, or it’s a Click-to-Run version that requires a different language pack type (e.g., Office 365 Click-to-Run language pack). Solution: Activate your Office product first. If you have Office 365, use the built-in language options via Control Panel > Language instead of the standalone MSI language pack. microsoft office 2016 english language pack 64-bit