Presuming this does not need to be generic beyond a string that's 2 digits followed by a space followed by Mary, try the following. If you find there are other cases where you're having a month announced when it shouldn't be then the regular expression would need to be tweaked to handle the alternatives. I am giving the regular expression you need to use, and the replacement string, each on its own line after a label to indicate which is is which, before I give the step-by-step instructions for adding that exception to the NVDA Default Dictionary.
replacement: \1 \2
Adding a Regular Expression match to the Default Dictionary
1. Hit NVDA+N,P,D,D NVDA Main Menu, Preferences, Speech dictionaries, Default Dictionary
2. Hit ALT+A to activate the Add Button or navigate to it and activate it.
3. In the dialog that appears, paste or enter a regular expression in the Pattern edit box.
4. Paste or enter the replacement you want to hear in the Replacement edit box. If you're using a capturing regular expression this may be a sequence of backslashes followed by the numbers of the capture groups you're using.
5. The Comment edit box should either have a comment that helps you to remember the purpose of this dictionary entry, which is preferable, or be left blank.
6. Leave the Case Sensitive checkbox unchecked.
7. The Type radio button should be set to Regular Expression.
8. Activate the OK button--
Brian - Windows 10 Pro, 64-Bit, Version 2004, Build 19041
It’s hard waking up and realizing it’s not always black and white.
~ Kelley Boorn