How can one differentiate between the letters of prolongation (alif, waw, ya) and the diacritics (fathah, dammah, kasrah) in the Arabic language?

We advise the questioner that knowing this is easy and accessible, and that the confusion may arise for English speakers due to their changing the dammah (short 'u' vowel) into a waw (long 'u' sound), which does not exist in the Arabic language. One must learn the Arabic language—reading, writing, and its grammar—to remove ambiguity, either in a school or with a private tutor.