Per the SDL Tridion Experience Manager Basic User Manual (login required) authorized users can send Components to translation, within XPM, with the option to add or create a new Translation Job while selecting .
The "to/from" column in the Translation Job is based on whether you initiate translation from a Source or Target Publication.
To be sure, what determines this "initiating" Publication context?
I'm assuming (hoping) it's the location of the selected Component's first localized parent "going up" (i.e. the functional equivalent to
ComponentData.BluePrintInfo.OwningRepository.IdRef as @NunoLinhares mentioned in this SO answer).