What is happening in the following examples taken from children's speech?

• I runned
• two mouses
• my foots
• he feeled shy
• he satted on the truck
• he drived himself.

The child is attempting to use plurals but not in the correct way. However, a sense of good logic is definitly present in what they are trying to say - (foots sounds more plausible that footses for example) They don't yet know that iregular pasts usually involve changing the middle letters rather than adding something on the end. (Eg. Mouse and mice rather than mouses.)