I am was pronouncing gestrig as [ˈɡɛstʀɪç], rhyming with mich [mɪç]. My Austrian colleague did not understand me until she said, oh, you mean [ˈɡɛstʀɪk]. Wiktionary lists both the [ɪç] and [ɪk] endings for fertig but only the [ɪç] ending for gestrig. She blamed it on her Austrian, but I'm no native speaker and certainly capable of mispronouncing words, and I certainly don't take wiktionary as gospel when faced with the word of a native speaker. Between the [ɪç] or [ɪk] endings for words that are spelt with the -ig suffix (fertig, gestrig, häufig, gläubig, etc.), is either pronunciation more standard than the other, or is it purely a regional differenc and is either pronunciation correct?