This is called having a leaky valve or a regurgitant valve.

这称为瓣膜渗漏或反流。

It was not pretty to hear when she spoke, for a sort of hissing, like steam from a leaky valve, but a comfort all the same out in the wilds.

她说话的时候听起来不太好听， 有点嘶嘶声， 就像从漏水的阀门里冒出蒸汽， 但在野外仍然是一种安慰。