The spelling of the name "Eirynn" is not straightforward. It is not a common name and there is no universal spelling convention. However, we can use the International Phonetic Alphabet (IPA) to explain the sounds in "Eirynn". The first sound "eɪ" represents the long "a" sound, the "ɪ" sound represents the "i" sound, and the second "n" sound represents the "n" sound. The "r" sound can be spelled with either one or two "r's". So, the most common alternative spellings are "Erin" or "Erinn".