When two vowels combine to make one sound, it is called a digraph. Long /a/ digraphs can be tricky. They can be written as ai as in nail, ea as in bear, eigh as in eight, ey as in grey, or ay as in tray. The long /a/ vowel sound is also expressed in the VCe spelling pattern, as in hare. It can be challenging for children to recognize and spell digraphs because they must recognize two letters that combine to make one sound, rather than recognize a one-sound, one-letter correspondence.