combinatorial method
...that due to a lack of bilingual inscriptions, most knowledge of the Etruscan language has been derived using the combinatorial method?
...that due to a lack of <a class="mw-redirect" href="./Bilingual_inscription" id="mwD3M" rel="mw:WikiLink" title="Bilingual inscription">bilingual inscriptions</a>, most knowledge of the <a href="./Etruscan_language" id="mwD3Q" rel="mw:WikiLink" title="Etruscan language">Etruscan language</a> has been derived using the <b id="mwD3U"><a href="./Combinatorial_method_(linguistics)" id="mwD3Y" rel="mw:WikiLink" title="Combinatorial method (linguistics)">combinatorial method</a></b>?