I have a similar problem. Rather than slowing down though, I have used the replay button. Is this advised or not? Or should I slow down a little and see if I can get it all in one take?
On lesson 4 it is possibly a little early for you to say what your aptitude is.
say however . .
. . that you are not just "learning" morse, but trying to build an automatic response,
when you hear the morse, the corresponding character pops into your head automatically.
After a period, you might even find that you don't hear the morse anymore - just the text.
This is "learned" by repetition - lots of it . . . .
you are better not fiddling with replay etc
listening to the lessons at a speed which allows you to spend ALL your time
hearing morse characters -> decoding them manually -> getting used to the association; that sound = that letter
repeat repeat repeat.
If you have high aptitude then almost no advise from this forum will be needed.
If you have normal or lower aptitude ( almost everyone ),
then you may well find that
tricks to speed things up and avoid the work needed will be counter productive.
If you go too slowly - you waste a bit of time.
If you go too quickly - it doesn't sink in properly as you may suddenly find out
you will need to start again, or more likey just give up, like about 90%+ of starters.
For my money - The Three Big Tips
( number three is the least popular in this forum - but probably only among Hams with no hearing issues )
1/ keep the character speed high enough that a character becomes ONE entity not a mix of separate dits and dahs
2/ Repeat repeat repeat listening, don't test test test
- don't type in your answers unless you can touch type already,
else you may find you can't "head copy" without starting again.
3/ If you can't hear it easily you can't learn to decode it.
Headphones are good.
Make sure you are somewhere quiet so you don't need loud morse hitting your ear drums.
If you don't have high aptitude then your hearing might not have a flat response,
so try a few audio frequencies to see if any are clearer than others.
If you have to go at 15/2 to get through lesson 40 then that's fine.
You will then speed up not give up.
Let us know how you get on.
Don't give up.
Good luck with it anyway .