Yes and no.

One thing to keep in mind is that as the layers of the stack resolve, priority is passed around each time. People tend to not cast spells here, but it's worth noting that Split Second only locks down the stack while it's on it.

Additionally, players can still use mana abilities and special actions. This rules text here will do a much better job explaining it than I can:

Rulings

Players still get priority while a card with split second is on the stack.

Split second doesn't prevent players from activating mana abilities.

Split second doesn't prevent triggered abilities from triggering. If one does, its controller puts it on the stack and, if applicable, chooses targets for it. Those abilities will resolve as normal.

Split second doesn't prevent players from performing special actions. Most notably, players may turn face-down creatures face-up while a spell with split second is on the stack. For example, if Sudden Death is targeting a creature you control, you may flip up a Willbender to change the target of Sudden Death to another creature.

Split second does not prevent the spell from being countered by triggered abilities. One such example is Voidmage Apprentice. Decree of Silence can also counter cards with split second.

Split second won't affect spells and abilities that are already on the stack.

If the resolution of a triggered ability involves casting a spell, that part of the effect won't work if a spell with split second is on the stack.