ohmu/third/drupal/mustikas11/add_translations.php

<?php
use Drupal\Core\StringTranslation\TranslatableMarkup;

// Lisa tõlge "Access denied" -> "Ligipääs keelatud" (et).
$translation = [
  'Access denied' => 'Ligipääs keelatud',
  'You are not authorized to access this page.' => 'Sul puudub õigus antud lehte vaadata.',
];

foreach ($translation as $source => $target) {
  // Kontrolli kas source juba olemas.
  $lid = \Drupal::database()->select('locales_source', 'ls')
    ->fields('ls', ['lid'])
    ->condition('source', $source)
    ->condition('context', '')
    ->execute()->fetchField();

  if (!$lid) {
    $lid = \Drupal::database()->insert('locales_source')
      ->fields(['source' => $source, 'context' => '', 'version' => ''])
      ->execute();
    echo "SOURCE_ADDED: $source\n";
  }

  // Lisa tõlge (et).
  $exists = \Drupal::database()->select('locales_target', 'lt')
    ->fields('lt', ['lid'])
    ->condition('lid', $lid)
    ->condition('language', 'et')
    ->execute()->fetchField();

  if (!$exists) {
    \Drupal::database()->insert('locales_target')
      ->fields([
        'lid' => $lid,
        'language' => 'et',
        'translation' => $target,
        'customized' => 1,
      ])
      ->execute();
    echo "TRANSLATION_ADDED: $source -> $target\n";
  } else {
    \Drupal::database()->update('locales_target')
      ->fields(['translation' => $target, 'customized' => 1])
      ->condition('lid', $lid)
      ->condition('language', 'et')
      ->execute();
    echo "TRANSLATION_UPDATED: $source -> $target\n";
  }
}