Unfortunately there is no setting to prevent Excel from automatically recognizing "11/19" and "11-19" as "19-Nov". However, you can stop it on a case-by-case basis by selecting the cells in question, going format->cells (or right-clicking the cells and selecting "format cells"), and on the "number" tab, selecting "text".
Hope this helps,
How do I stop the dates from appearing in excel when I type 8-11 (as in I want it to be a time, 8 o'clock to 11). I cannot find the option to turn the auto-date function off. I have office 2003. Thanks!