Layer objects visibility after 1st visit.

I'd have the progressive layers contain all the words rather than single words. For example, let's say you have 10 words.

Layer 1 has word 1. 

Layer 2 has word 1 and word 2. 

Layer 3 has word 1 and 2 and 3.

Create layer 10 first with all the words and proper alignment. Then duplicate it for the other layers and remove the words.

Thanks Tom,
This however does not address the issue when I hit the previous button.
Alpha

Sent from my iPhone

If you use the default layer properties which is to not show previous layers, you should see that the progressive reveal works as noted.

I see what you mean, however not having all words on each layer make easier to dim learned sections.

What I am looking for  is how to hide again next  layers when one navigate to the previous layer button. For instance if I am on layer #3 I see the content of layer 1, 2 ,3. If go to previous layer , #2, I want the layer #3 content to  disappear, I see only layer 1 and 2.

You'd have to have triggers to show the layers you want. 

In that case, all layers should be visible and then you'd need to create a trigger to show and hide layers that you desire.

Thanks.
That’s what I was planning to do. It is just à peine to have all those triggers.

Sent from my iPhone

How can I hide some objects on a layer once the timeline of  another layer starts without hiding the layer containing those objects ?

Without seeing your file - you could place shapes over the objects you want to hide when the new layer shows

Wendy's tip is probably the easiest because you can move objects on the timeline. Of course, you could make it more complex using variables. 

Thanks all for the assistance. I am all set on this aspect.