V-ERG
(使)变粗俗;（使）变粗鲁
If someone's behaviour or speech coarsens or if they coarsen it, they become less polite or they begin to speak in a less pleasant way.
例句
Her voice has deepened and coarsened with the years...
随着岁月的流逝，她的声音变得低沉粗鲁起来。
He had coarsened his voice to an approximation of Cockney.
他让自己的口音变得粗俗起来，接近伦敦东区的发音。