What is the definition of a digraph?

A digraph is defined as a group of letters that combine to represent a single sound, making option B the correct choice. This definition captures the essence of how digraphs function in language, as they are crucial in phonics and spelling, particularly in the context of multi-sensory structured language education.

For instance, in the word "chop," the letters "ch" form a digraph that creates the unique sound associated with that combination. This concept is foundational in helping students decode and spell words, linking letter combinations to their corresponding sounds.

In contrast, other options do not accurately describe a digraph. For example, two words written together doesn't convey the specific sound representation that a digraph does. Similarly, while two vowels next to each other can sometimes form a digraph (as in "ai" or "ou"), this description is too narrow and does not encompass all possible digraphs that may involve consonants or other letter combinations. A writing pattern is also too vague and does not specifically pertain to the phonetic aspect of letter combinations that characterize digraphs. Thus, option B is the most precise and relevant definition within the scope of language education.