I've been reading the WordPress's codex recently, and noticed that WordPress is using a term called GUID. According to codex:The term GUID stands for Globally Unique Identifier. It is a field  that is intended to hold an identifier for the post which a) is unique  across the whole of space and time and b) never, ever changes. The  GUID field is primarily used to create the WordPress feeds.Let's assume we have a website with it's posts written in English. Now web decide to translate the website's posts to Russian, and publish it under another domain as it's sister website.According to WordPress's codex, even after the translation, the translated posts will still have the same GUID as the original website.The question is, will this affect indexing? Will google or other search engines/feed readers consider the translated posts as duplicate?
Do search engines consider GUID in indexing?
seo;indexing;multilingual;feeds
When it comes to search engines duplicate content is not based on the GUID rather it is based on the content itself. How the search engine companies do this is a closely guarded proprietary secret but in very broad strokes is based on comparing the content of the page to other pages already in the index. Where page content is the same but in different languages then duplicate content penalties don't come into play as it is clearly demonstrated that the content is targeted at two different markets based on language.As for the GUID aspect of the question search engines don't really consider the GUID of a wordpress article at all. The GUID is used in wordpress to uniquely identify the article across the internet, however search engines use the URL of the page in question to identify the page. If two pages have the same GUID search engines won't have any issue with it unless the content of the page is the same with the same language.So based on your question given that the two sites which will have pages with the same GUID will be in different languages then you won't have any issues with search engines or feed readers.