Edit in JSFiddle

$(document).ready(function(){
   var table = $('#example').DataTable({
      ajax: 'https://gyrocode.github.io/files/jquery-datatables/arrays.json',
      dom: 'Alfrtip',
      alphabetSearch: {
         column: 0
      },
      language: {
         alphabetSearch: {
            alphabet: '#АБВГДЕЁЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯ',
            infoDisplay: 'Показать',
            infoAll: 'Все'
         }
      }      
   });
});

<h3><a target="_parent" href="https://www.gyrocode.com/projects/jquery-datatables-alphabetsearch/">jQuery DataTables AlphabetSearch:</a> <a target="_parent" href="https://www.gyrocode.com/projects/jquery-datatables-alphabetsearch/examples/basic/localization/">Localization</a></h3>
    
<table id="example" class="display" cellspacing="0" width="100%">
   <thead>
      <tr>
         <th>Name</th>
         <th>Position</th>
         <th>Office</th>
         <th>Extn</th>
         <th>Start date</th>
         <th>Salary</th>
      </tr>
   </thead>
   <tfoot>
      <tr>
         <th>Name</th>
         <th>Position</th>
         <th>Office</th>
         <th>Age</th>
         <th>Start date</th>
         <th>Salary</th>
      </tr>
   </tfoot>
</table>

<hr>
<a target="_parent" href="https://www.gyrocode.com/projects/jquery-datatables-alphabetsearch/">See full article on Gyrocode.com</a>