"Bitterful" is not a commonly-used word and is not found in most dictionaries. It appears to be a combination of "bitter" and "full" and could be interpreted as meaning "filled with bitterness". In terms of phonetic transcription, "bitterful" would be pronounced /ˈbɪtər.fəl/. The "bitter" part is pronounced with a short "i" sound and the "er" sound at the end, while the "ful" part is pronounced with a short "u" sound and a hard "l".