TheCodeBreakers
Sometimes they used new hieroglyphs whose first sound represented the
letter desired, as a picture of a pig, "rer," would mean /r/. Sometimes the
sounds of the two hieroglyphs differed but their images resembled one
another. The horned asp, representing HI, was replaced by the serpent,
representing /z/. And sometimes the scribes used a hieroglyph on the
rebus principle, as in English a picture of a bee might represent b; thus a
sailboat, "khentey," stands for another Egyptian word khentey, which
means "who presides at"—this latter being part of a title of the god Amon,
"he who presides at Karnak." These procedures °f acrophony and the
rebus are essentially those of ordinary Egyptian writing; it was through
them that the hieroglyphics originally acquired their sound values. The
Egyptian transformations merely carry them further, elaborate them, and
make them more artificial.
The transformations occur in funerary formulas, in a hymn to Thoth,
annaabi.ee 
