AI OnAI Off
The languages that you select there are the ones that get extended language support. EPiServer Find can index any language but you will only get the extended language support for the selected languages. Hope that answers your question
Means that Find will do stemming on those languages when indexing and searching.
The "Add Developer Service", gives an option of selecting the languages. What does this is used for? I selected 3 out of the available languages. We have our website in 10 languages and I selected only 3 thinking only the pages in selected languages shall be indexed. However, on trigerring the indexing job manually in admin mode, I could see that it is indexing the pages in all the languages. So what does the language selection mean in "Add Developer Service"?