JSFiddle - React, Tailwind, and code Playground

by userTrue

HTML

<div>
  <input name="lang" type="radio" value="en" checked onchange="translate(value)">En
  <input name="lang" type="radio" value="ru" onchange="translate(value)">Ru
</div>

<select id="month" translate>
  <option value="january">January</option>
  <option value="february">February</option>
  <option value="may">May</option>
</select>

JavaScript

document.addEventListener('DOMContentLoaded', main);

function main() {
	const lang = document.querySelector('[name="lang"]').value;
  translate(lang);
}

function translate(lang) {
 const currentlangMap = langMap[lang];
 if (!currentlangMap) return;
 
 for (const el of document.querySelectorAll('[translate]>*')) {
    const text = el.textContent;
    if (text && currentlangMap[text]) {
    	el.textContent = currentlangMap[text];
    }
 }
}

const langMap = {
	ru: {
  	January: 'Январь',
    February: 'Ферваль',
    May: 'Май'
  },
  en: {
    Январь: 'January',
    Ферваль: 'February',
    Май: 'May'
  }

}