How do we plan sign-language access for our wedding without treating it as an optional extra?

My Deaf cousin asked whether there would be an NZSL interpreter for the ceremony and speeches. My partner pointed to the printed ceremony script and asked, "Wouldn't this cover it?"

My cousin uses New Zealand Sign Language and has said that an interpreter is what would help him follow those parts of the day. The speeches won't all be printed, and I don't want to decide on his behalf that reading the script is the same experience.

An interpreter provider has given us an initial NZ$650 quote, subject to the schedule. My partner says we didn't budget for it. We did budget for a flower arch costing more than that. I don't think he means our cousin matters less, but our conversation keeps treating one choice as fixed and the other as a problem.

The [Ministry of Social Development's event guidance](https://www.msd.govt.nz/about-msd-and-our-work/work-programmes/lead-programme-work/information-and-support/accessible-meetings-and-events.html) recommends asking attendees about their needs, allowing time to arrange NZSL interpreters and supplying material in advance.

How do we revisit the budget and running order without leaving my cousin to argue for the access he's already requested?