Is possible to compare to audio samples with cross-correlation
No. If the words are pronounced with a different speed or intonation (prosody), or by different speakers, the cross-correlation won't have any significance.

A solution more robust to changes in prosody is to use audio features which are less dependent on pitch (such as MFCCs), and a comparison method that is robust to local time stretching (such as DTW or a distance between HMMs). It will still perform poorly when comparing a recording of two different persons saying the same word.