for $nom in //element/data[@type='type']
let $textn := $nom/following-sibling::data[@type='string']/text()

let $adj := $nom/parent::element/following-sibling::element[1]/data[@type='type']
let $texta := $adj/following-sibling::data[@type='string']/text()

return if($nom/text()='NOM' and $adj/text()='ADJ')
then string-join(($textn, $texta), ' ')
else ()