How can I add language selection to the user profile in "my account" settings I'm currently allowing users to switch language with the "Language switcher" block, but I would like have this as part of the user profile that is managed with the "My Account" settings page.

Is it possible to add this as a field? Adding a field is no problem, but can I make it refer to the language setting that is normally controlled by the language switcher block? I'm using Drupal 7.
The language setting is already present in the account settings page, I was misguided by the first part of the description "This account's default language for e-mails, ..." and skipped over the rest that read "... and preferred language for site presentation." doh!