It's really easy to create a node or a term programmatically in Drupal 8. Here is the script to create term programmatically.
$term = Term::create([
'name' => 'Apple',
'vid' => 1,
]);
$term->save();
But a small change in this simple script will allow you to added translation for this term as well.
$term = Term::create([
'name' => 'Apple',
'vid' => 1,
]);
// Add translation.
$term->addTranslation('ar', ['name' => 'Apfel',]);
$term->save();
Similarly, translations can be added to a node or any other entity programmatically.