Most Irish wedding speeches are delivered in the English language as most of the audience expect it to be and most of them anyway will probably speak or understand it.
For people who are fluent Irish speakers, it would be suggested that you do deliver part of your speech in Irish. This can be done at the start of the speech, at the end of the speech or throughout the speech. It is important that what you say is said in English too either word for word or in a different way, as your guests can feel left out if they do not understand what you are saying / have said.
For people not born in Ireland and who are getting married in Ireland where English is not their first language, it is expected that most of the speech could be delivered in their native tongue, though not all of it. One would have to make an attempt at delivering part of the speech or saying a few words in the English language.
If you are wondering what to say in the Irish language or in your native tongue, consider wedding blessings, wedding poems and opening and closing your speech in Irish.
Your wedding guests always appreciate people speaking in their native tongue, once they know what they are saying or that it is translated for them.
Finally, if some of your main wedding party and guests are from a particular part of the world, welcoming them in their native language or saying a few words during your speech would make them feel really at home.
Whatever language(s) you use during your wedding speech, cover everything that your specific speech is supposed to cover, prepare well, practice, look forward to it and don’t forget to smile!