You’d need to provide the source texts as the first file and the target texts as the second file!
It is advised to use the sourceLang and targetLang options to specify the language of the source and target texts.
Options
Options are passed as query parameters in the URL.
The option untranslated can use any DNF combination of the described values.
Here only a comma separated list of values for an OR combination is meaningful.
inferred from filename - e.g. strings.en-us.xml infers en-us.
This specifies the language of the target texts.
untranslated
combination of missing, empty, equal.
missing
Translate all units that match this configuration. missing: not contained in target file. empty: has empty value in target file. equal: has the same value in source and target file.