Curious, why would anyone order a banner in Spanish that can’t write in Spanish or have someone in their mix that can. I tried to translate a request for safety related signs for a company years ago, only to find out that there are many ways to say the same thing. There is formal and street common. It’s sort of like us trying to understand legalese in a contract. I have customers that hand me text that doesn’t make a bit of since but are adamant about no changes.
So my advice is leaving it to the customer and go on to the next job.