Seating families with 2 different languages?

I’m also in the same situation and was trying to figure out seating arrangements. Most of my fiancé’s family speaks Portuguese and my family speaks only English. I can’t do assigned tables because I don’t really know all of the people my fiancé invited. I’m having to guess a little. Since my ceremony and reception will be in the same room, I’m thinking of having ushers seat my family on the left and my fiancé’s family on the right so that each family and friends will be together and maybe it won’t make anyone feel uncomfortable. That’s about the only thing I can’t think of so far but my situation is a bit different since I won’t know specifically everyone who is coming for his side and we will most likely have about 100 people or more.

I’m having a “bilingual” wedding. Is mostly in Spanish than English for the ceremony but most of the signs I made them in both language. The itinerary for welcome bags are on English one side and Spanish the next. You just have to accommodate them all when possible. Not everything needs to be both languages but they’ll appreciate the effort. For the ceremony you can have the officiant say everything in English than Spanish or skip thru. One verse English and one Spanish. That’s up to you.
As far as sitting I’m not a fan of having 10 kids alone in a table without supervision. I say have them all sit with family. If your budget allows it maybe have a reserve area with a table for them to have games and coloring books after dinner. This way they can mingle. Kids are not afraid of playing with others even when they don’t understand. I wouldn’t worry about them.

I'm separating them most likely. Most of FW's family and some of her friends ds only speak Thai, but I can fit them all at one table luckily. One or two of them plus FW know English so I'm hoping those people can help a bit, lol

I would recommend keeping kids with their family, and make sure there is something at the table to keep them occupied. Separating families seems like a good idea to me, but it is not a bad thing for people to question something or be uncomfortable with the unknown. Encourage learning and questions. We thought about having a guide in the program explaining the different traditions that we will be incorporating, so that both sides understood why a certain moment was important.

Our ceremony will be in Spanish/English, and the reception will be in Spanish mostly with some English. My family (English-speakers) is very small, and my FW's family (Spanish-speakers) is very large, and most of our friends understand Spanish, so it wasn't a problem for us to decide to incorporate Spanish into everything. I would definitely recommend making things bi-lingual as much as possible in your case. That goes for the wedding website, invites possibly, program, signs, ect... in order to make everyone included in festivities. Bi-lingual vendors would be a good touch too, such as the officiant and DJ.

Good luck, hope to hear other great bi-lingual wedding tips!