Skript does not understand the event

[Aawqq2112]

is not walk on dirt or grass:
   apply slowness 2 to the player for 1 second

 

[Tymen van Essen]

can you try if this works:

on walk on any block:
    if event-block is not dirt or grass:
        apply slowness 2 to the player for 1 second

 

[Aawqq2112]

can you try if this works:

on walk on any block:
    if event-block is not dirt or grass:
        apply slowness 2 to the player for 1 second

not in work

 

[Mashhhyyy]

This is the way I would do this without SkQuery, May not be the most efficient but it should work. Simply run the command /scenario start to begin checking and /scenario stop to stop.

command /scenario start:
    permission: scenario.start
    trigger:
        set {_bc} to true
        while {_bc} is true:
            loop all players:
                if block under loop-player is dirt block:
                    apply slowness to loop-player for 1 second
                else if block under loop-player is grass block:
                    apply slowness to loop-player for 1 second


command /scenario stop:
    permission: scenario.stop
    trigger:
        set {_bc} to false

If you'd like it to be constantly checking, use this and restart your server, I warn you though it may cause lag.

on load:
    set {_bc} to true
    while {_bc} is true:
        loop all players:
            if block under loop-player is dirt block:
                apply slowness to loop-player for 1 second
            else if block under loop-player is grass block:
                apply slowness to loop-player for 1 second

 

[oHeckGage]

if you add skQuery to your server, you can use the on any movement event.

on any movement:
    if block under player is dirt:
        apply slowness to player for 1 second

 

[Minecoll_YT]

or

on step on dirt:
    #do smth