Which of the following activities helps children combine words to form compound words?

The activity that focuses on manipulating sounds in words is effective for helping children combine words to form compound words. This approach encourages children to explore how different sounds and syllables come together to create new meanings. By engaging in this manipulation, children actively participate in constructing language and understand the relationship between individual sounds, syllables, and the larger words they form.

When children manipulate sounds, they are essentially playing with the building blocks of language, which fosters their ability to recognize and create compound words by blending two distinct words or sounds into one. For instance, when children combine "sun" and "flower," they learn to understand how the individual meanings contribute to the overall concept of a sunflower.

The other activities mentioned do not specifically focus on the construction of compound words. Syllable deletion might involve removing parts of a word rather than combining them, onset and rime combination deals with the initial sounds and letter groups of words, and listening to sounds focuses on auditory discrimination rather than the active creation of words. Hence, manipulating sounds in words is the most aligned with the objective of forming compound words.