Modifiers matching duck:

• jealous,
• pushy,
• slobbery,
• tenacious,
• rare,
• optimistic,
• here,
• common,
• aggressive,
• brash,
• short-tempered,
• smaller,
• zany,
• insecure,
• bullying,
• determined,
• domestic,
• boastful,
• marine,
• native,
• large,
• larger,
• unusual,
• wild,
• small,
• paranoid,
• indigenous,
• breeding,
• lisping,
• daffy,

Simple categories matching lisping:

• duck,
• person,
• child,
• villain,