"Meyer suspects one of the factors leading to this divide can be found in the numbers: according to her book, there are 500,000 words in the English language, but only 70,000 in French. This means that Anglophones are more likely to have the exact word to say what they want, whereas Francophones must often string together a series of words to communicate their message."
If true (I suspect a methodology shenanigan there) I really doubt this is a factor. Very few French or English speaker will have a mastery of 70,000 words, to say nothing of 500,000.
According to one source [1] adult English speakers are typically in the 30 000 - 50 000 range. [1] https://wordcounter.io/blog/how-many-words-does-the-average-...
Total vocabulary of the language is certainly not a limiting factor.
"Countries like the US and Australia are low-context cultures where people generally say what they mean and mean what they say. However, France, like Russia and Japan, tends to be a high-context culture, where “good communication is sophisticated, nuanced and layered."
I (and many of my French expat friends) have the opposite experience with US: shallow enthusiasm, shallow friendships, fake excitement. Feels like Americans present a simple layer that is actually a mask, whereas French actually show their inner feelings more easily (which ends up being a bit messy, like I suspect everyone is).
I was told several time (and experienced) that Americans love to say yes, and not follow through, which is a pretty rude thing in France. "Why don't we have lunch one day?" "you should come to my house!" "Let's make something together" Apparently these are non-committal statement in US. In France they are. That's why being able to say no is far more important.
Etymologically, "French" comes from "Franks" the name of the germanic/celtic tribe that lived there. It also gave the word "frankness". I never thought much of it but after working with several foreign colleagues, I really think there is a reason why this tribe and this trait got mixed together.
In France we value frankness and we don't find it commendable to hide your feelings or your opinions. If you promise something you have to follow through. You are going to receive a lot of "non" because of that, because "oui" really means "oui".