Don't pet or speak to a person's guide dog. Guide dogs are at work, even when sleeping under chairs. Hearing loss is not related to intelligence. People can acquire hearing loss after they've learned to speak. Those who have been deaf or hearing-impaired since birth may be difficult to understand and may need to communicate by sign language or other gestures.
Hearing aids can be just partially effective.
Even when amplified, sounds may seem distorted to someone with hearing loss. 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.