Final answer:
The smallest unit of sound recognized by the speakers of a language is the phoneme, a basic sound unit of a given language. To notice a temporal difference between sounds from separate speakers, on a day with the speed of sound at 340 m/s, speakers would need to be at least 0.34 meters apart.
Step-by-step explanation:
The smallest unit of sound that speakers of a language can recognize is called a phoneme. It's the most basic sound unit of a given language. Various phonemes are combined to create morphemes, the minimum units of language that impart meaning. For example, phonemes like "ah" versus "eh" differentiate in meaning within the spoken language.
To answer the question about the perception of sound from speakers at different distances, we need to consider the speed of sound and the ear's ability to differentiate sounds that arrive at least 1.00 ms apart. On a day when the speed of sound is 340 m/s, the minimum distance between two speakers that produce sounds which are recognizably different in arrival times at the ear would be calculated by multiplying the speed of sound by the minimum time difference discernible by the ear. This calculation would be 340 m/s * 0.001 s = 0.34 meters. Therefore, the speakers would need to be at least 0.34 meters apart for their sounds to arrive at noticeably different times at the ear.