The word "forthspeaker" is spelled using the IPA phonetic transcription as /fɔːθspikər/. The first part of the word, "forth," is pronounced with the "o" sound as in "more" and "north." The "th" sound is pronounced as in "thought" and "theme." As for the second part, "speaker," it is pronounced with the "e" sound as in "seek" and the "r" sound at the end is pronounced slightly with the tongue tapping the roof of the mouth. Overall, the word "forthspeaker" is phonetically spelled to accurately reflect its pronunciation.