Some children continue to use these processes beyond an appropriate age, and their speech may become hard to understand as their vocabulary increases. Phonological approaches provide a systematic and efficient method for removing error patterns in a child’s speech. This handout discusses four phonological approaches—Minimal Pairs, Multiple Oppositions, Maximal Oppositions, and Treatment of the Empty Set. All of these approaches are evidenced-based and may significantly reduce the time that unintelligible children spend in treatment