The word 'spawn' means to produce or create something, especially in large numbers. For example, fish lay many eggs in the water, which is called spawning.
You pronounce 'spawn' like this: spawn (rhymes with 'dawn'). It sounds like 'sp' followed by 'awn'.
The word 'spawn' comes from the Old French word 'espon', which means 'to lay eggs'. It has been used in English for a long time to talk about fish and other animals that produce eggs.