I'm trying to rename a managed package custom object's related list label through the Translation workbench using this article as a guide.
When selecting "English" as the language and the Setup Component as "Custom Field", my custom object, Payment Type, does not appear in the Object dropdown.
When I change the language to Spanish, however, it does.
The object is in a master-detail relationship which may be relevant.
There is currently no supported Custom Labels / Translations API from Apex, the Web Services API, or SOQL that you could use to achieve what you're after (the Map<String,List<String>> with the master language value as the key). Click here to get this on the Product Management top priorities list!!! (NOTE: there IS a very much insane way that you might be able to achieve this through Apex by doing a PageReference.getContent() and using a Visualforce Page as a utility to return the desired translated values, but I do not recommend this route at all).
However, I think that you can avoid the need through this by addressing the root cause of your problem: your Web-to-Lead form sending back values in the local language of the user. If you can get the Web-to-Lead form to always send back values to your database in a unified master language, while presenting these options to the user visually in their local language, then your problem is solved.
So, the goal is for your Web-to-Lead form's generated <select> tag corresponding to the Salesforce Picklist field in question to have child <option> nodes whose value attributes are in the Master Language, but whose content / text is in the local language.
Example:
You have a Picklist Field "Do you need a Home Mortgage?" in Salesforce with entries "Yes","No","Very Much". You have translated these into, say, Spanish, with values "Sí","No","Muchíssimo". Now, if your Web-to-Lead form looks like this:
<select id="do-you-need-a-home-mortgage">
<option value="Yes">Sí</option>
<option value="No">No</option>
<option value="Very Much">Muchíssimo</option>
</select>
then you're golden --- your database will be populated appropriately.
So, I'm assuming you're currently populating the text/visible portion of these fields appropriately, so I'm assuming you have access to both the PicklistEntry values and public-facing, translated labels. BUT, if you don't, you can get these from the Web Services API or from within Apex through the DescribeFieldResult for this Picklist field, and then doing a getPicklistValues() call.
You have to add the languages into the community via the community builder. Once enabled, the translations from the translation workbench will start to come through.
Best Answer
For custom objects that are part of a Managed Package this is done slightly different, because you have to override the values provided in the package:
The reason that you only have to do this for 'English' is that the Managed Package's language is probably English and thus they have provided only the labels for that 1 language. So only 1 set of labels to override.