Final answer:
The most effective technique for teaching phonemic awareness segmentation is to pronounce a word and have students position counters to represent each sound.
Step-by-step explanation:
The instructional technique that is most effective in teaching students the phonemic awareness skill of segmentation is pronouncing a word and having students position plastic counters in a row to represent each sound. This hands-on activity allows students to concretely manipulate objects, which represents each sound they hear, thus reinforcing their understanding of how words can be broken down into individual phonemic parts. It is an engaging way to visually and physically demonstrate segmentation.