The spelling of the word "more robustuous" may seem confusing, but it can be easily deciphered with the help of IPA phonetic transcription. The correct pronunciation of "robustuous" is /rəˈbʌstjuəs/. By adding the word "more" to the beginning, we create the comparative form, indicating that something is even more robust and vigorous. While the spelling of this word might appear unusual, it follows the typical rules of English pronunciation and can be pronounced correctly with some practice.