I don't know how to interact with sister-in-law's family.

Colombian women are pretty loud. I'm sort of afraid of them and I don't know what to do because my brother's fiancee is from Colombia. Their wedding is in a couple of months and I'm scared to interact with her family. They're not particularly friendly tbh. The men are pretty laid back but the women are so strict and loud. Do you guys have any suggestions on how I can present or interact with them properly without being intimidated?