To get someone's attention, touch that person lightly, wave or use another physical sign. Speak clearly, from a close proximity. Yelling or exaggerating articulation will not make you easier to understand. Don't be embarrassed to rely on written notes. They can promote effective communication.
Lip reading can be an invaluable aid.
Only about 30 percent of spoken language is understood through lip reading. People with Speech Impairments Speech disabilities run the gamut from slight lisps to total speech loss. Be patient when a person with a speech impairment is speaking. Most people with speech impairments can communicate, but doing so usually requires mutual effort. Speech impairments are not related to intelligence.