Dear Ayya,
I don’t know if it will help, but there is a option on YouTube to slow down the speed of a video which you can access through the settings (see the picture attached). I gave it a try at 1/2 speed, and it does sound a bit funny (maybe not so understandable in a few places), but it is definitely slower.
Also, YouTube does offer a transcript (see “More” highlighted in the picture) for some videos (oddly, I’ve noticed one isn’t available for the first in this video set, but is available for the rest), however, I understand transcript generation is automated and in many instances is utter gibberish.
In addition, may I also offer my thanks to Ajahn Brahmali (and Russell), I followed this series and found it very helpful.