Sat, and Three Sibilants Collapsing in Three Directions

Sat is the second of the two plain s letters and, in the standard account, the one that took over two proto-Semitic consonants at once. Where the reconstruction gives three sibilants, Ge'ez kept two letters and merged the remaining pair into this one. Hebrew took a different route, keeping a separate samekh and using the shin sign for two values. Syriac has semkath and shin. Arabic has sin and shin. Every language in the family reduced the three, and no two of them reduced them the same way.

The result is that a table of correspondences between the Ge'ez and Hebrew sibilants cannot be a simple list of pairs. Sat answers to the Hebrew samekh in some words and to the shin in others, depending on which proto-Semitic consonant the word carried. That is not an uncertainty about the letters. It is a fact about the sound changes behind them, and it is why a comparative dictionary of the kind Wolf Leslau compiled for Ge'ez gives cognates word by word rather than letter by letter.

The atlas records the relation from sat to the Hebrew samekh as debated for the same reason, with the alternative stated on the relation rather than suppressed. A relation presented as settled would be tidier and would misdescribe what the sources say.