"Birds" in French is spelled oiseaux, and is pronounced "wazo".

The "oi" makes the "wa" sound. The "s" makes the "z" sound Then you have "eaux" ALL TO MAKE The "O" SOUND

FOUR LETTERS TO MAKE THE "O" SOUND

It's like if we spelled "balloons" like "balleauxeauxns" JUST BECAUSE WE CAN.