lean method to replace text in html?

I need to replace texts on multiple pages by clicking a simple button. What is the leanest switch between two languages?

var text1=document.getElementById(‘english’);
var text2=document.getElementById(‘swedish’);

const swap = () => {
  if(english.classList.contains("hidden")){ //if english contains class 'hidden'
    english.classList.remove("hidden"); //remove hidden class from english
    swedish.classList.add("hidden"); //add hidden class to swedish
  }
  else{
    english.classList.add("hidden"); //add hidden class to english
    swedish.classList.remove("hidden"); //remove hidden class from swedish
  }
}

.hidden{
  display:none;
}

<button onclick="swap()">Switch Text</button>

<div class="content">
  <div id=“english>
    <h1>Welcome</h1>
    <p>English text</p>
  </div>
  <div id=“swedish” class="hidden">
    <h1>Vällkommen</h1>
    <p>Swedish text</p>
  </div>
</div>

this only changes text in the first div. I need to have language change applied across the site.