How can I manage different languages and email marketing in the Dawn theme?

Store Design
1

Hello! I want to merge all my online stores in one store with different languages - ENG, LT, LV and RU, but I have a question about:

  1. Banner. What are the options when switching languages, that the banner with the selected language will also change?
  2. Email Marketing. When customers sign up to receive email information from our store, how can we differentiate customers when we send out, for example, a weekly discount offer?I mean, how will we understand the language of communication with each of our customers?
    I hope You can help me with this issues.
    Looking forward answer from You!
2

@HAMAMELIS

Hii,
Can you please share your Store URL