You are making the mistake of responding to what the current bad code is doing.
What you should instead be doing is to imagine what needs to occur instead.
The mouseover handler needs to show the pause button, which is what the showPause function does.
The mouseout handler needs to show the speaker, which is what the showSpeaker function does.
Currently both of those handlers incorrectly use the playButton function instead.
Can you figure out how to fix that?