Paramètres à l'intérieur de la chaîne localisée Laravel
Laravel message localization uses named, not numeric, parameters.
Rewriting your example message:
'string1' => 'Welcome :user, Please meet :other',
You can now use, for example:
trans('string1', [ 'user' => 'Ainsley', 'other' => 'Hayden' ]);
Excited Elephant