The word "sarcastical" is sometimes used as a variation of the more common word "sarcastic." The phonetic transcription of this word is /sɑːkæstɪkəl/, which is pronounced sahr-kas-ti-kuhl. The "-al" at the end is added to the root word to turn it into an adjective that describes something as sarcastic in nature. However, it should be noted that "sarcastical" is not considered a standard or widely recognized word, and it may be seen as nonstandard or incorrect in some contexts.
Bitterly satirical or ironical; taunting.
Etymological and pronouncing dictionary of the English language. By Stormonth, James, Phelp, P. H. Published 1874.