Philberthe is not a commonly known word and it is difficult to provide a phonetic transcription for it. However, it is likely that the word is a variation of the name "Philbert" and may be spelled as "Philberte" or "Philberta". In IPA transcription, these variations would be /ˈfɪlbərt/ and /ˈfɪlbərtə/ respectively. Without further context and information, it is impossible to accurately determine the correct spelling or pronunciation of "Philberthe".