"Neossoptile" is a word used in biology to describe a feather that first appears on a bird during its growth process. The word is spelled as "nee-oh-sop-tyl" in IPA phonetic transcription. The stress falls on the second syllable, which is pronounced with an "oh" sound. The "s" in the middle of the word is doubled to represent a consonant cluster. The unique spelling of "neossoptile" reflects its specific meaning and scientific origin.