[MaDDoGo]

I looked at this and I think this would read the information from langinfo.xml:

const TiXmlNode *pLocale = pRootElement->FirstChild("locale");
if (pLocale && !pLocale->NoChildren())
{
const TiXmlNode *pLangLocaleName = pLocale->FirstChild("LangLocaleName");
if (pLangLocaleName && !pLangLocaleName->NoChildren())
m_defaultRegion.m_strLangLocaleName=pLangLocaleName->FirstChild()->Value();

const TiXmlNode *pRegionLocaleName = pLocale->FirstChild("audio");
if (pRegionLocaleName && !pRegionLocaleName->NoChildren())
m_defaultRegion.m_strRegionLocaleName=pRegionLocaleName->FirstChild()->Value();
}

And would read this:

<locale>
<LangLocaleName>Español (España)</LangLocaleName>
<RegionLocaleName>es_ES</RegionLocaleName>
</locale>

Sorry if it's not the place but I don't know how to do it better.

Then in the options, maybe you can adapt the addon's way of reading tags (but instead of Addons name you read locale's name) using the es_ES file scheme.