sentences:  There are many more vowel phonemes in English than there are single vowel letters ("a", "e", "i", "o", "u", "w", "y").As a result, some "long vowels" are often indicated by combinations of letters (like the "oa" in "boat", the "ow" in "how", and the "ay" in "stay"), or the historically based silent "e" (as in "note" and "cake").The consequence of this complex orthographic history is that learning to read can be challenging in English.