Divide the word "emerald" into three syllables: "em," "er" and "ald." Basic syllable structure indicates that a word is usually split at any single middle consonant that occurs between two vowels. So in this case, breaks occur after the "m" and the "r."
Pronounce the first syllable ("em") out loud. This is the accented syllable, which means it receives the most emphasis when you pronounce the word. The syllable begins with a vowel, so there is no onset present; however, it does contain a nucleus in the "e" and a coda in the "m." The syllable is pronounced "ehm."
Sound out the second syllable, "er." Like the first syllable, this one begins with a vowel and thus has no onset. Because this syllable consists of only a vowel and an "r," it is "r-controlled," which means the "r" sounds strongly influences the pronunciation. The syllable is pronounced "ur."
Pronounce the final syllable, "ald." There is no onset for this syllable, and the beginning "al" provides the nucleus. The vowel sound is present in the pronunciation, but the "l" sound is clearly dominant. The coda is the hard "d" sound.