Pronunciation has to do with the act of uttering a single letter, syllable, word, sentence, or whole address. This concerns correctness.
Enunciation has to do with careful, distinct utterance so that any word or any part of a word is completely audible. This concerns distinctness.
Articulation has to do with the act of gracefully and skillfully manipulating those organs of speech necessary for the correct pronunciation and distinct enunciation of words. This concerns skillfulness.
At least a part of the following exercises should be practiced daily, preferably in the morning. A few minutes’ practice is a splendid tonic for the tasks of the day.
I. For the Lips and Jaw
1. Repeat e a aw ah o oo. In doing this extend the lips and use a relaxed jaw.
2. Repeat again, giving a rising inflection to each. Then give each sound the falling inflection, and then the circumflex inflection.
3. Intone them on successive pitches. Be sure you have pure vowel quality.
4. Whisper the sounds e aw permitting the jaw, in the latter sound, to drop completely relaxed each time.