Hello, and ... hear me out :D

I was not sure how to phrase the question in the headline correctly, so that it does not sound offensive. I came across something, where I thought I saw a pattern if you will, but was not even able to correctly phrase a google search, which would have led to anything on the topic. So I was hoping someone here can enlighten me with some cultural insights - maybe in the following context, there is also no cultural pattern at all and I am all making that up in my head ... no idea. So, I beg your pardon, if I am totally making this up :D

So, the situation is the following:

In the past, I was working as an engineer on international construction sites and in that role have had the pleasure to also been to Egypt on two sites. It was my role, amongst other things, to teach staff on site software and systems our company sold to the site. I had the impression with several people there, that when I was telling and showing them things in hard- and software, that they would kind of mumble what I had said just a sentence earlier, either to themselves or to ... me? ... like as an approval that they had understood what I said, or so? It was irritating to me first, because I felt interrupted, but after some time accepted it as a quirk or so.

Now, years later, I am in a different position. I work in a software company and we have a new employee from Tunisia. He has just finished his Masters Degree and is now starting fresh with us and as such has a steep learning curve. I noticed also in our online meetings (Corona ...) that, in a 1:1 with me or in bigger groups with senior developers, he shows somewhat of the same behavior, that he is ... kinda quietly in the background confirming, mumbling stuff that others have said before, like he is approving or so ... now my colleagues are in the same situation, they are irritated by it and assume that indeed he does NOT understand and is just parroting them just to say something.

So I was wondering, whether this are two totally unrelated things, or whether there is maybe a pattern? Is this maybe a sort of approval-thing that you guys and gals do?

Hope I could explain my thinking :)

Thanks for any feedback