Is it possible to make only one field in a content type language neutral? If you have a text field, that you do not want to be translated (i.e. language neutral) as in a field for an email address, how do you set just that one field to be language neutral, while leaving the rest of the fields in the content type multilingual (enabled, with translation under workflow settings)? I've tried toggling the checkboxes under "Content Translation" but I think that's just for the Translation Management modules translation jobs handler, not for the actual field settings itself.

The idea is to not have to enter an email address twice in both, for instance, English and Spanish since the value will be the same in both language. Otherwise you have to enter the value in each language to get it to show up in that language.
I don't believe that it's possible to configure the language type of fields and translate per field. Not in Drupal 6 anyways.

This shouldn't be a problem anyways. When you translate a node, drupal makes a copy of the original node, which means the e-mail address will be pre filled with the correct value.

The does require some extra work when editing, but if you really wanted to, you could create some custom code, or maybe setup a rule, to keep that field in sync with the other translated nodes.