小声 + Verb
小声 means "in a low voice" or "quietly" and describes the volume at which someone speaks or makes sound. It can function as an adjective or adverb, as in 小声说 (say quietly) or 小声地说话 (speak in a low voice). The opposite is 大声 (loudly).
宝宝在睡觉,请小声说话。
Bǎobao zài shuìjiào, qǐng xiǎo shēng shuōhuà.
The baby is sleeping; please speak quietly.
他小声对我说了一句"谢谢"。
Tā xiǎo shēng duì wǒ shuō le yī jù "xièxie".
He quietly said "thank you" to me.
图书馆里大家都在小声讨论。
Túshūguǎn lǐ dàjiā dōu zài xiǎo shēng tǎolùn.
Everyone in the library is discussing quietly.