it would be useful if one could configure information about the additional email addresses in portal(-ext).properties.
Users and organizations may have additional email addresses defined in Control Panel. The labels (Email Address, Email Address 1, Email Address 2) may be changed in Language_xx.properties but:
1) the labels are always the same, regardless of the type (User, Organization, ...)
2) there can only be 3 email addresses because they seem to map to numeric key entries (10004, 10005, ...) in the database
A better and more flexible design would be to allow for a more dynamic configuration e.g.
organization.email.addresses=email-address-2, email-address-3, email-address-4
email-address-1: Business email
email-address-2: Administrator's email
email-address-3: Janitor's email
email-address-4: Security officer's email
email-address-5: Private email
Thus, for an organization there would 3 different email-address types and the user would have 2 different types.
Today (as a workaround), you may define custom fields for organization and user and label the fields with the email address label. Unfortunately the custom field key labels can't be translated into different languages. In order to not confuse the users, you will also have to hide the email address section in the control panel.
I guess this enhancement may also be valid for other "statically" defined types in Liferay.