In the area of pronunciation, minimal pairs can be problematic. Minimal pairs are words which are ALMOST pronounced the same. To the unfamiliar ears, these words sound exactly the same; in other words, they are homophones. This is especially true when English is spoken quickly or not carefully. Wylcomenetwork.com has available istudycards on minimal pairs (vowels). (contains 6 sets of istudycards)
The audio for Minimal Pairs: Vowels can be accessed at studyguides.com. Minimal pairs (consonants), English vowels and English consonants would be good buys to help you better understand minimal pairs (vowels).
Also, videos on more general discussions on pronunciation, metaphoric English, idiomatic expressions, grammar, collegiate vocabulary, prefixes, roots, suffixes and more, go to carralaficklin.com. At Carralaficklin.com you can also find video on Spanish, Spanish expressions, Spanish grammar, Spanish relationship with English and English relationship with Spanish and the other Latin-based languages. There even a discussion on verbs and the subjunctive mood in English versus Spanish.