This post addresses how to teach the vowel sound as in the word BOY. The vowel in the word boy is actually considered to be a diphthong. There are eight diphthongs in English…please read under the diphthong page above for information on how to teach the other seven diphthongs.
A diphthong is a sequence of two vowel sounds produced in a single syllable with one sound dominant. A diphthong is made up of the nucleus and the glide. The nucleus is the longer dominant vowel of the diphthong (and is the first part of the diphthong) and the glide is the shorter, less stressed vowel of the diphthong (the glide is the second part of the diphthong).
as in words such as: boy, oil, voice, coin, foil
What you see above is how we transcribe the diphthong as in the word boy. This diphthong is a back round to a high front diphthong…this is in reference to how it is produced inside of the mouth.
How this diphthong is produced inside of the oral cavity:
The velopharyngeal port is closed, the back and middle portion of the tongue is slightly raised with elevation for the first part of the diphthong (the nucleus), the mouth is open with the lips rounded and slightly protruded and it is voiced. Voiced means that you are vibrating your vocal folds to make this sound. Next, the lip rounding relaxes and the tongue briefly rises.
The children I have been working with all seem to have difficulty with the glide part of the diphthong. My experience has been that they are capable of producing the nucleus….however delete the glide completely. When given a verbal and visual cue…and when just producing the diphthong in isolation….they are capable of producing both the nucleus and the glide. However….once in a word….the glide is deleted.
To improve your little one’s ability….it is best to start off with words that are consonant-vowel words (and do NOT have a consonant that follows the vowel). An example of this would be the following…..best to start off with words like: COY……..and work towards words like: COIL. Both of these words start off with the consonant C…..followed by the same diphthong…however, in the word: COIL…..the consonant L ends the word….making it a little more challenging.
HOW TO TEACH THE DIPHTHONG: 
When addressing this diphthong…I like to start off with the non-speech exercise of having the child make a pucker with her lips….next retract her lips for a smile. This oral motor exercise will help her get her lips and tongue into position for the production of the diphthong in the word boy. After you have practiced this oral motor exercise she should be ready to put some sound to it…..I like to use a mirror in order to give the little one feedback so that she sees what she is doing with her lips.
Have your little one practice the Aw sound (this is like the sound you hear in the word: LAW)…..now have her hold the sound….next add the long E sound…..
Use the cue below to help your little produce the long E sound.
E…….stretching out the E sound during production. Use the visual cue that follows to help your little one “see” that the long E sound continues.
One of the ABA teachers I work with called this the “taffy” cue……so imagine that you are holding a piece of taffy between your hands….held together by your pointer fingers and thumbs…..then you are going to pull the taffy apart…..stretching your fingers/hands apart…..the picture above is the best one I could find to give you the visual cue…..remember to start at midline(the middle of your body) with both hands together….only pointer and thumbs touching…..then as you stretch your fingers out….make the E sound…..you should stretch to the length of your shoulders…
After your little one can produce the aw sound and the long E…have them practice in syllables such as:
Next practice in syllables that do not end in a consonant such as:
Next practice the same words above…but now with an ending consonant…this will definitely make the production of the glide portion of the diphthong more challenging. I have found that as soon as there is a consonant at the end of the word…the glide is deleted…..so when I practice the word list below…I would be sure to really exaggerate the Long E sound…..then follow by the ending consonant…please post any questions…
Remember some of the words are nonsense words…it does not matter…the point is to get your little one to go from a consonant….to the diphthong…and then end the word or nonsense word with another consonant.
Now when I work with the two little ones that I see for “diphthong therapy”…..this is the order of “diphthong therapy”
1.Nucleus sound..aw sound only
2. Glide sound….long E sound only
3. Syllables…..aww followed by long E
4. C-V words: use list above
5. C-V words in phrases, then short sentences, longer sentences, conversation
6. C-V-C words: use list above
7. C-V-C words in phrases, then short sentences, longer sentences, conversation
Hope this was helpful.