The spelling of the word "YSSAS" can be explained using the International Phonetic Alphabet (IPA). Firstly, the first letter "Y" is pronounced as an /i/ sound, similar to the "ee" sound. The double "S" in "YSSAS" is pronounced as a /s/ sound, and the following "A" is pronounced as an /æ/ sound like in "cat". Finally, the second "S" in "YSSAS" is pronounced as another /s/ sound. So, the IPA phonetic transcription of "YSSAS" would be /i'sæs/.