"Latissa" might be written in IPA phonetic transcription as /ləˈtisə/. The first syllable starts with a schwa sound, followed by a /t/ sound. The second syllable starts with an unstressed /i/ sound and ends with a stressed /sə/ (pronounced like the end of "osa"). The spelling of this word appears to be unusual, as it combines the Latin prefix "lati-" (meaning "wide" or "broad") with an unusual ending. Without more context, it's unclear what "Latissa" might refer to.
There doesn't appear to be an official or widely recognized etymology for the word "Latissa". It is possible that "Latissa" could be a proper noun or a derivative of another word or name in a particular context, but without more information, it is difficult to determine its origins or meaning.