<p>After reading the post regarding homework help, I have decided that this technically isn’t a homework question (where I ask what’s the answer to something).</p>
<p>When you conjugate first declension nouns, for a noun ending in “ia” like patria, would the plural dative form be patriis or patris? I tried looking in the textbook and online websites, but couldn’t find a thing explaining this.</p>
<p>You do not keep the double ii’s in some cases of second declension nouns (e.g. filius/fili/filii for sg. nom., sg. gen., pl. nom. respectively).</p>
<p>To second the answers you already got, its definitely patriis. (double i)</p>
<p>For almost all latin nouns (i don’t think there are any exceptions but im not 100% sure in August) take the singular genitive (in this case patriae) and remove the genitive ending (ae) to get the stem. Add the endings to that. So, patri- is the stem, -is is the ending, patriis is the dative/ablative plural.</p>