Life is uncertain. Eat dessert first.
Ernestine Ulmer

The words work, turn, bird, and early are all spelled with a different vowel, yet the vowel sound is the same. This frequently happens when a vowel is followed by the letter r. The sound remains /ɘr/. Non-native speakers are frequently tempted to pronounce the vowels as they are spelled, and they make the common mistakes of saying “wore+k” instead of “were +k” (for work) and “two+rn” instead of turn. Sometimes they will even pronounce bird as “beer +d.”