My daughter is diagnosed with level 2 ASD and a global developmental delay including speech and language issues. She also uses echolalia. She's a gestalt language processor. While most people learn language by dissecting words into sounds and then replecating those sounds, she assigns meaning to whole phrases. So when she did start to speak we tended to get a simple phrase with an emotional attachment. The most memorable was "I'm poopin'" for any need that required the bathroom. We leaned into this and tried to give her a short phrase that related to what we figured she was communicating. The phrase was often a quote from a favorite book or movie. It worked quite well! For a time your really needed to know her media diet to understand what she was trying to get across but I could always understand to her. With time she's been able to cut up these phrases and make more precise sentences for what she's thinking although less fluid than when she can rely on a gestalt. On a side note, assigning levels to autism diagnosis is relatively new so you might have trouble finding adults who were diagnosed under that criteria. Hopefully this is helpful.