Horses nearly always sense our energy and intentions long before we open our mouths LOL. Some horses like to be talked to a bit, sung to, enjoy your humming etc. and enjoy soothing happy voices and laughter, but I hardly speak around them because horses are instinctively silent creatures and it rubs off if you merge with their ways. Body language (if one actually knows how and sets a goal to speak fluent horse with their body as well as intentions) is crucial to any relationship with any horse, absolutely.
If you want to get a horse's attention, this works for a number of things - I've done it mainly with horses who need confidence: keep your eyes (soft) on theirs while you turn your head to one side, then turn your head to the other side, all the while keeping your eyes on them, just do that once or twice. They will nearly always give you a curious and interested look and come to you. Your intention behind the look they also intuit beforehand :)
I believe horses have different abilities to cope with human ups and downs, they are individuals just as we are, and I tend to steer clear of them if I'm upset. Not that I'm some Polyanna around them constantly, because they can see through that bs too LOL.