隔壁房间传来含糊的说话声。

Muffled voices came from the next room .

youdao

主要的区别是澳大利亚人习惯说话有点含糊，而且突出元音发音。

The main difference is that Australians are used to speaking a little vaguely, and they emphasize vowel pronunciation.

youdao

他一再读错单词，而且说话含含糊糊的。

He repeatedly mispronounced words and slurred his speech.

《柯林斯英汉双解大词典》

So, Darwin writes, "Man has an instinctive tendency to speak, as we see in the babble of our young children, while no child has an instinctive tendency to bake, brew or write."

查尔斯·达尔文写到,"人类拥有说话的本能倾向,我们会看到幼儿含糊吐字,然而儿童却并不具有烘焙,酿酒或是写作的本能倾向"

耶鲁公开课 - 心理学导论课程节选

I think the main difference is Australians tend to mumble a little bit and to draw out their vowels,

我想，主要的区别是澳大利亚人习惯说话有点含糊，而且突出元音发音，

有趣的澳大利亚英语 - SpeakingMax英语口语达人