In this example, apart of the phoneme files for your map and region, as it is very specific, I think that the only solution is to translaite it in the "Dictionary.voice" file inside the zip file of the voice.
Open your voice zip file (with a version under 4.0 of winzip), inside the folder i18n is the file "Dictionary.voice". You can open it with notepad and inserte the next:
Save the file, say yes if it ask you to update the file inside the zip, and test you voice. In this example it is only for a translation, but if there were a lot, you should do it by hand, one by one. I do not know if there is a specific phoneme for Scotland