mid-14c., "sound repeated by reflection," from Latin echo, from Greek ēkhō, personified in classical mythology as a mountain nymph who pined away for love of Narcissus until nothing was left of her but her voice, from or related to ēkhē "sound," ēkhein "to resound," from PIE *wagh-io-, extended form of root *(s)wagh- "to resound" (source also of Sanskrit vagnuh "sound," Latin vagire "to cry," Old English swogan "to resound"). Related: Echoes. Echo chamber is attested from 1937.
1580s, "practice or discipline for a specific purpose," from Medieval Latin praxis "practice, exercise, action" (mid-13c., opposite of theory), from Greek praxis "practice, action, doing," from stem of prassein, prattein "to do, to act" (see practical). From 1610s as "a collection of examples for practice." In 20c. given a particular sense in Marxist jargon.
<a href="https://www.etymonline.com/word/echopraxia">Etymology of echopraxia by etymonline</a>
Harper, D. (n.d.). Etymology of echopraxia. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/echopraxia