As opposed to most major European languages, English writing does not provide enough information for the reader to unambiguously identify the sounds of words by just looking at the letters used. Instead, you need to learn the pronunciation and writing of every single word as a symbol separately, and many times need to add interpretation to be able to get the correct sounds.

It is the only major European language that needs an additional pronunciation guide for each word in its dictionary.

Consider the following phrase: There are words in English like read, which sometimes can be read as read, and sometimes as read. Current English spelling does not provide a clear way to indicate which sounds should be used, especially in the last two instances. 

This book explains the evolution of English and isolates the main 15 vocalic sounds of English, which can help a student of English to improve pronunciation.