Complex sentence: Even when learning sign language Genie continued to use and invent her own gestures, but while she continued to use her existing gestures for individual phonemes she started creating new ones to convey a semantic meaning.
Split into simpler sentences: Even when learning sign language Genie continued to use and invent her own gestures, although she began to change the way she created them. She continued to use her existing gestures for individual phonemes, but started inventing new ones to convey a semantic meaning.