NotebookLM Video Overview: Is it worth asking it to use language at a lower level?

The reason I am interested in the answer to this question is because I like the idea of students being able to generate content based on transcripts of their spoken output (or of their writing.) But it should be accessible to them and their classmates.

I've examined at least 9 different podcast-producing tools and analysed the length and level of the podcasts and the speed of delivery. The conclusion of that study is that this technique is most approproate for B1 and above students as the podcasts are mostly at B2. Many of these tools allow students to slow down the speed of delivery.

My comparison of podcast-producing tools all used the same recording and its transcript: The Story of the Spanish Couple on the Titanic recorded by a good B1 student in 2014.

Here I discuss how useful NotebookLM's Video Overview could be for a B1 level learner.

This is the uncustomised Video Overview:

Text Inspector         C1 59%

Text Analyzer B2 61 GSE

Average B2+ 60

Length in words      1044

Length in time        5 mins 45 seconds

Speed in w.p.m      182 w.p.m

This means that the Video Overview would be a bit difficult for a B1 student

Here's the version where I used the customisation, "Please use simple English suitable for a student of level B1 on the CEFR scale"

As you can see, it is slightly shorter and slightly easier.

Text Inspector      B2+    55%    (C1 59%)

Text Analyzer B1+ 58 GSE    (B2 61 GSE)

Average B2 56.5          (B2+    60)

Length in words     759                    (1044)

Length in time        4 mins 10 seconds    (5 mins 45 seconds)

Speed in w.p.m      182 w.p.m    (182 w.p.m)

My conclusion is that it is probably worth customising the Video Overview in this way. Could I have asked for the delivery to be a bit slower? It's still hard for a B1 student at full speed, but using NotebookLM it can be played at three-quarter speed 137 words per minute