I went to http://unabridged.merriam-webster.com/

The 'Word of the Day' is pointillistic. The icon to say the word did not work for me.

I tried using four different web browsers. This could be a web site issue.

Same problem.

They should'n use <iframe src="wav"> but the <audio> tag instead. This is their mistake. Their code cannot work here.

works on chrome and safari tho... ?

Unfortunately, Merriam-Webster has not configured their website correctly. You may reach out to them to inform them of the issue. The issue can also be reported here: https://webcompat.com/

In the past we did suggest using a bookmarklet to convert such a not working element to an audio tag.

javascript:(function(){
var cE='audio',eE=document.querySelectorAll('object,embed,iframe,audio');
for(i=0;E=eE[i];i++){
if(E.nodeName=='AUDIO'){E.play()}
else{
N=document.createElement(cE);
N.setAttribute('src',E.src||E.data);N.setAttribute('controls','');
N.setAttribute('autoplay','true');
E.parentNode.replaceChild(N,E)
}}
})()