Which word ends with a voiceless sound?

The word "looks" ends with a voiceless sound because it concludes with the /s/ phoneme, which is produced without the vibration of the vocal cords. Voiceless sounds, like /s/, are characterized by a lack of vocal cord vibration, in contrast to voiced sounds where the vocal cords do vibrate, such as the /z/ sound at the end of "badge" or the /b/ sound at the end of "cab". This distinction is crucial in phonetics as it influences pronunciation and listening comprehension in language learning. The words "please" and "badge," for instance, end with the voiced /z/ and /d/ sounds, respectively, which further emphasizes why "looks" is the only option to end with a voiceless sound. Understanding voicing is essential for both teaching pronunciation and helping learners distinguish between different sounds in English.