Be aware of through observation, inquiry, or information.
Tip: not to be confused with the similar sign THINK.
The origin of KNOW came from a compound KNOW+BRING (anticipatory assimilation).
Gloss: IX2 fs-Roberta | IX1 KNOW IX2 SINCE GROW-UP(IX1)
English equivalent: She has known Roberta since she was a child.
Watch how the signer establishes referents in space and maintains them (e.g. GROW-UP in the same spatial reference of the referent, IX2 or 'she').