Publisher saves most of its data to its own custom tables which mimic ExpressionEngine's native exp_channel_titles and exp_channel_data tables. Through the use of ExpressionEngine's hooks the data form these tables are used to replace the data from the native tables when displayed on the front-end or within the control panel.
Does Publisher create duplicate entries for each language?
No. Since Publisher saves its data in its own tables ExpressionEngine is only aware of 1 database row for each entry.
Does Publisher translate custom field names or Grid columns in the CP?
Publisher will not translate custom field type names, help text, or Grid column titles. Publisher only supports translation of entry content.
Will Publisher translate entry comments?
No, Publisher does not support translation of entry comments.
Does Publisher work with X add-on?
This is a hard question to answer, but the first place you should check is the Requirements and third-party add-ons pages. If you know the add-on does not save its data in a custom database table, then most likely Publisher supports it. If it saves its data in a custom table, such as the Channel Images add-on, then it may not work with Publisher. If in doubt, just ask us.