"Throwing the sponge" is an idiomatic expression meaning to give up or quit. The pronunciation of the word "sponge" is spelt as /spʌndʒ/. In this case, the "o" is pronounced as "uh" or /ʌ/ sound, and "ge" is pronounced as "j" or /dʒ/ sound. Even though this phrase doesn't contain any particularly tricky phonemes, it serves as a reminder that English spelling can often be unpredictable and requires careful attention to detail.