In order to encourage someone to speak more clearly there are five things that I teach.
1- Take a deep breath- clear speech begins with
adequate air. People with low volume or soft voice benefit from taking a deep breath. A full breath allows for increased volume (loudness).
2- Separate your words- Someone whose speech is unclear
can be immediately more clear, by separating their words. Instead of "gonna and “wanna” ..teach "Going to” and “want to” or “want a” pause between words. This also helps with improving oral reading clarity.
3- Pronounce all sounds in a word- "popcorn” has 2 p’s, If one leaves out a sound ie /p/, tell him "I did not hear the 2nd /p/. Can you say it again? Make sure you pronounce 2 /p/’s.
4-Pronounce all syllables in a word- the word "elephant" has three syllables. Make sure he says ALL three. Demonstrate "e-le-phant" distinctly, pronouncing each syllable.
5-Look at the listener- it is easier for us to understand one with imprecise speech, if they look at us when they speak. Many sounds, that sound alike, LOOK differently on the mouth. i.e "net" and "met"