<?php

return array(
    // Native language name
    'language' => array('it_IT' => 'Italiano'),
    'englishlang' => array('it_IT' => 'Italian'),
    // Possible locale for language
    'locale' => array('it_IT' => 'it_IT,it_IT.utf8,it_IT.utf-8,it_IT.UTF-8,it_IT@euro,italian,Italian_Italy.1252'),
    // Encoding of the language
    'encoding' => array('it_IT' => 'UTF-8'),
    // Direction of the language
    'direction' => array('it_IT' => 'ltr'),
    // Possible aliases for language
    'alias' => array(
        'it' => 'it_IT',
        'italiano' => 'it_IT',
        'ita' => 'it_IT',
        'italian' => 'it_IT',
        'it_IT.ISO8859-1' => 'it_IT',
        'it_IT.ISO8859-15' => 'it_IT',
    ),
);

<?php

return array(
    // Native language name
    'language' => array('it_IT' => 'Italiano'),
    'englishlang' => array('it_IT' => 'Italian'),
    // Possible locale for language
    'locale' => array('it_IT' => 'it,it_IT,it_IT.utf8,it_IT.utf-8,it_IT.UTF-8,it_IT@euro,italian,Italian_Italy.1252'),
    // Encoding of the language
    'encoding' => array('it_IT' => 'UTF-8'),
    // Direction of the language
    'direction' => array('it_IT' => 'ltr'),
    // Possible aliases for language
    'alias' => array(
        'it' => 'it_IT',
        'italiano' => 'it_IT',
        'ita' => 'it_IT',
        'italian' => 'it_IT',
        'it_IT.ISO8859-1' => 'it_IT',
        'it_IT.ISO8859-15' => 'it_IT',
    ),
);

Add "it" as locale alias for it_IT
Add "it" as locale alias for it_IT
