The languages can be specifier using the attribute "lang". If this attribute is not specified, the fields will be the same for all languanges.
<products>
<product external-reference="demo-1">
<name lang="en">Name</name>
<name lang="fr">Non</name>
<description lang="en">Product description</description>
<description lang="fr">Description du produit</description>
<price>19.99</price>
</product>
</products>