"Tastest" is an incorrect spelling of the word "tastiest", which means having the most delicious flavor. The correct spelling of the word contains the letter "i" after the letter "t", which is pronounced as /aɪ/. The IPA phonetic transcription of "tastiest" is /ˈteɪstiəst/. It is important to use correct spelling and pronunciation to ensure effective communication in both written and spoken forms of communication.