Any culture that is able to communicate with words and complex language is hands down at an advantage over the culture that cannot. During high school I had a friend who studied American Sign Language and she could also speak normally. She enjoyed being a translator for deaf-mute students and she told me how complex ideas are communicated more simply in ASL. From what I remember, her example was that in regular language the statement "you are fatter" would be perceived as rude but in ASL, the fact that they use less "words" to communicate, that same phrase would be pretty much the best way to tell someone that they look like they have "gained some weight."
The second part of the experiment was so much easier to do because I was finally allowed to use my words and we didn't all feel anchored to each other anymore like we did in the first part of the assignment. I was able to follow my mom and brother around and it was easier to keep their attention on me, so that let me feel like I was more in control. This part of the assignment was kind of contagious because then my mom and brother would also try speaking in monotone with me and sometimes we found it difficult to tell when we were joking or being serious. Sometimes, we were unable to differentiate when a sentence was actually a question or a statement, because in monotone the voice pitch stays neutral even at the end of a question, so it sounds like a regular sentence. I found it relatively easy to keep my facial expressions still as I spoke but it felt like I was multitasking the entire time and I had to constantly remember not to move my eyebrows or my cheeks as I spoke. I also noticed that I'm not very dependent on my hand expressions when I speak English as much as I am when I speak Spanish, probably because I am less fluent in Spanish and my vocabulary is aided by using hand expressions.
I think our physical and vocal expressions play a huge role in telling stories and communicating ideas, not only for adding to the context of what we are trying to say but especially to keep the other person or group interested in the conversation. Speaking in monotone would get boring pretty quickly because there is no life being added to the conversation. Without emotion, there is no telling when someone is angry or sad or anything that tells us the state of their being. It would not be enough to see a person crying if they couldnt express their words with some sort of variety in their vocal pitch.