Is that fourth vowel a u or an o?
schwaThree of the five vowels in lanceolate are unstressed. The ear gets a blur and the fingers pick a letter.
heard aslanceulate
spelledlanceolate
saidLAN-see-uh-layt
It is an o. The word is lanceolate.
That vowel belongs to lanceola, the small lance the word is named for. In Latin the o was pronounced; in English it has collapsed into an unstressed uh, which is exactly what a u would be used to write. The letter stayed and the sound left.
Also filed here
lanseolate lanceollate lanceolat lanceelate lancealate lanceolute
Each one has a page of its own. All 7 spellings of lanceolate.