Data which user saved make the initial value of checkbox

Background

In my app, users can choose multiple languages which they're able to speak on their profile edit page (users/edit.html.erb) from checkbox. Many-to-many relation is already written, so multiple data can be saved properly.

Now, when users came back to their profle edit page, all the checkbox are displayed in a blank. I would like to display languages with "checked" which user chose and saved.

users/edit.html.erb

<li>
 <div class="col-1">Spoken languages:</div>
   <div class="col-2">      
     <label><input type="checkbox" name="language[]" value="1">Japanese</label>
     <label><input type="checkbox" name="language[]" value="2">English</label>
     <label><input type="checkbox" name="language[]" value="3">Chinese</label>
     <label><input type="checkbox" name="language[]" value="4">Spanish</label>
  </div>    
</li> 

What I tried to do

I searched this kind of function, but I only found how to make a specific initial value (such as always check "English"). I would be grateful if someone give me advice.

Version

ruby 2.6.4p104 RubyGems 3.0.3 Rails 5.2.3