To display content in both languages, as Ismet suggested, you can store previously translated texts of “Task Names” and text fields (ex. “Resource skills”) into other customized fields.
Then with a very simple macro, you can choose to display all texts in language1 or in language 2.
Send us your need, it seems very simple: we can build a macro for you for a small price as we are (too) specialized in Project VBA developments since 1998.
If you need on-the-fly content translation, that is to say you often need to translate new texts/tasks/resource/comments/texts, you are just in time J: starting from Office 365 launch on January 29th, Project tasks can be automatically translated and published in different languages in a collection of multilingual SharePoint 2013 SaaS sites (in that case: Project management sites).
With new “catalog-enabled lists” feature, SharePoint 2013 can be configured to perform automatic translation and publication of lists, i. e. Project Task lists too (As you know, Project tasks can be synchronized with SharePoint tasks lists).
For your information, after the official Project Online/SharePoint Online launch on Feb. 27th. (professional side of Office 365), we will offer a SaaS service with all new SharePoint 2013 benefits, including a free sandbox for selected project managers having professional needs like you have, where this automatic translation and publication feature will probably be activated.
If your translation need is important, feel free to contact us in March and ask for a free access to one of our SaaS Project Management sites sandboxes.