The Wiktionary entry for Komma shows 2 plural forms: Kommas and Kommata. However, my German teacher told me that only the form die Kommata is correct, and the second is used by the people that don't know the correct form.
The answer about the English plural from "comma" suggests, that in English the form commata is practically unused. How does it look like with German language? Would a typical German understand, what is meant, when he/she hears the word Kommata?