Learn Farsi: آیا شما در این همایش علمی شرکت کرده‌اید؟ - Have you participated in this scientific conference?

This is the present perfect tense, used to talk about past actions that are relevant right now. It is formed using the past participle kardeh plus the personal ending -id (which is a shortened form of hastid). If it were the simple past tense ('you participated'), it would simply be sherkat kardid.

Is the word âyâ strictly required to ask this question?

No, in spoken Farsi you usually just raise the pitch of your voice at the end of a regular sentence to make it a yes/no question. âyâ is a formal question marker used mainly in writing or formal speech, which perfectly matches the formal tone of asking about a scientific conference.

How do you pronounce the connection between hamâyesh (conference) and elmi (scientific)?

You connect them using the Ezâfe, which is a short 'e' sound added to the end of the first word. You pronounce it as hamâyesh-e elmi. This grammatical link is required when a noun is followed by an adjective, even though it is rarely written out in the Farsi script.

Does the compound verb sherkat kardan (to participate) always take the preposition dar (in)?

Yes, just like in English, when you want to say you are participating 'in' something, you use the preposition dar before the event. Here, it is placed right before the noun phrase, making the structure dar in hamâyesh-e elmi.