How do I add the phonetic contact fields to a contact on iOS 5 when using an iPhone 4?

I can confirm after testing that these fields are not available on the iPhone 4 in iOS5, although they are available on the iPhone 4S.

However, if you have your contacts synced with Address Book on the Mac, you can add the field to the contact card via the Add Field menu item under Contact, and the field is then sent to your iPhone on the next sync. I am not able to confirm if you can do this via the iCloud web interface directly.

It's looking like a bug.

On the phone, if I have a contact that already has a first and last name entered, there is still an option to add a further first and last name field. If I add and fill in the fields, then view the contact in iCloud.com when it has synced, it shows the phonetic first and last names as already in use, with the details I entered. If I remove the additional fields, and then try to add them back using the phonetic first and last names fields which are available on the website version, then sync back they sync to the additional first/last name fields as originally shown.

So, in short it looks like they forgot to include the word "phonetic" on iOS5 running on (at least) iPhone 4, the fields are there, and they sync correctly, they just do not show properly.