Okay, this herd of African bush elephants probably doesn’t celebrate National Grammar Day with the rest of us. But scientists are studying the sometimes surprising ways in which African elephants converse—including the ultra-low frequency vocal sounds they make that are imperceptible to humans. These subharmonic ‘rumblings’ vibrate through the ground and can be felt by other elephants on the bottoms of their feet. And who knows, maybe these sounds follow a kind of grammatical structure we don’t yet comprehend. But perhaps we should start by trying to master English grammar.