In order to convert OLK14 messages from Microsoft Outlook 2011 for Mac to standard EML, you need to open/import it in that program and export as EML.
Convert Microsoft Outlook for Mac message file to Email message.
We found one software available in the database for this conversion.
Apple macOS / Mac OS X software - convert olk14 to eml on OS X
Mac version of the popular e-mail client and personal information manager from Microsoft
Convert from olk14 file format
The table with program actions contains information about what each program is capable of doing with their files. This may be a good pointer for further searches for certain file conversions and help you find the converter you are looking for if our search result is insufficient for you. However, it is far from perfect and may sometimes show results which are not really usable because of the nature of the software handles the files. So a conversion that appears as possible, just because of matched actions, may in fact not be possible.