A digraph is a combination of two letters that represent a single sound. Here are some examples:
* "sh" in "ship"
* "ch" in "chair"
* "th" in "thin"
* "ph" in "phone"
* "ck" in "luck"
* "ea" in "meat"
* "ai" in "rain"
Digraphs are common in English and other languages, and they can help us understand the pronunciation of words.