I have two characters in the port of Zaitun in 14th Century China. They are just off a trading vessel from Europe and are about to commence with trade and purchase. I have written the following:
"Both Cepa and Matzerath have learned some basic greetings which they yell at the top of their voices. These are not the formal nor polite greetings of social interaction, but rather . . . "
My question, open to all and sundry, is should I use the phrase "at the top of their voices". How else does one yell? Yet I feel this is emphasis which fits with their surroundings, and not excess.
But I'm not sure.