This self-teaching instruction workbook (in American English) helps with:

spelling vowels (long, short, and vowel groups) spelling consonants (including blends) words with multiple syllables distinguishing between homophones examples of tricky proper nouns challenge spelling lists (could be handy for upcoming spelling bee competitions) several practice exercises (with answers to all problems at the back of the book) suitable for all ages, from about fourth grade up (including teens or adults)

This book avoids technical jargon (like diphthongs and phonemes) so that people of all ages and backgrounds can understand the ideas. This makes it handy for English as a second language (ESL) students, or anyone who isn’t fluent with the technical vocabulary conventionally used to teach spelling and phonics. (However, for those who would like to learn the terminology, these terms are collected in an appendix.