The second one is charging hourly. We tend to prefer hourly fees on projects that are particularly open ended or very small scope. Our hourly rates are currently between $60 and $120 per hour depending on who is doing the work.
The word sonder exists, though. It means to probe, and in a more specific use, to test the depth of something. The word sound (as in the water feature) is a cognate, both related to the Old English sund meaning to swim, or the sea. I can't really think of an English equivalent that's specific beyond mere awareness.
yoder definition: Proper noun 1. A surname . 2. Any of the places in the U.S. named after people with the family name Yoder. Anagrams 3. DoreyOrigin The family name is from the German Joder, the name of a clan in the Canton of Bern, Switzerland;...