Assimilation is when sounds in a word start to sound the same as each other. Imagine you have a bowl of candy and it has different colors like red, blue, and green. If you start to mix the candy together so it all looks the same, that's like assimilation in language! When sounds in a word are spoken close together, they start to blend and sound like each other, just like the candy in the bowl. So instead of hearing the different sounds clearly, we hear them as just one similar sound. This can happen in many languages and can make words sound different from their original form.