Things without life - Instruments of music.
Whether pipe - This instrument (αὐλὸς aulos) was usually made of reeds, and probably had a resemblance to a flageolet.
Or harp - This instrument (κιθάρα kithara) was a stringed instrument, and was made in the same way as a modern harp. It usually had ten strings, and was struck with the plectrum, or with a key. It was commonly employed in praise.
Except they give a distinction in the sounds - Unless they give a difference in the “tones,” such as are indicated in the gamut for music.
How shall it be known ... - That is, there would be no time, no music. Nothing would be indicated by it. It would not be suited to excite the emotions of sorrow or of joy. All music is designed to excite emotions; but if there be no difference in the tones, no emotion would be produced. So it would be in words uttered. Unless there was something that was suited to excite thought or emotion; unless what was spoken was made “intelligible,” no matter how important in itself it might be, yet it would be useless.