Yep, no problem. I found out that is happening only when text fields are grouped, single ungrouped text fields are working as expected.

piklist('field', array(
    'type' => 'group'
    ,'field' => 'group_test'
    ,'label' => __('group test') 
    ,'columns' => 12
    ,'fields' => array( 
    			array( 
			'type' => 'text'
			,'field' => 'fritto_1_ita'
			,'columns' => 8
			,'label' => 'fritto 1'
			,'value' => 'Coccole con prosciutto e stracciatella'
			,'attributes' => array('placeholder' => 'Italiano')
			)
			,array(
			'type' => 'text'
			,'field' => 'fritto_1_eng'
			,'columns' => 8
			,'value' => 'Deep-fried dough balls with ham and stracciatella cheese'
			,'attributes' => array('placeholder' => 'Inglese')
			)
			,array(
			'type' => 'text'
			,'field' => 'fritto_1_prezzo'
			,'columns' => 3
			,'value' => '8 €'
			,'attributes' => array('placeholder' => 'prezzo')
			 )
			)
		)
	);

piklist('field', array(
			'type' => 'text'
			,'field' => 'single_test'
			,'columns' => 8
			,'label' => 'single test'
			,'value' => 'Coccole con prosciutto e stracciatella'
			,'attributes' => array('placeholder' => 'single test')
			)
	);