It appears that question has been answered. Phonetic spelling is really a fine tuning feature or for use with languages other than English. Some letter combinations have a different sound depending upon the language being spoken. For most uses it will be un-necessary. Glad you have it working. Talk Designer is a fine feature and works well. It's a shame the Poser manual does not give enough information about it.

In another thread you asked about Mimic files for M4. You do know that you can make the visemes for M4 so you can use him in Talk Designer. Any figure for that matter can be used if you make up the viseme file. A viceme file is just a call to a corresponding morph on the figure. It is a bit of work but pretty straight forward.

Someone in that thread wanted DMC files for the DAZ horse. I don't do Studio but one could make vicemes for it and use it in Talk Designer easily enough.