Like all AI devices that use National Language Processing or NLP, Alexa does not understand all voices easily. But she learns to understand her people over time. She does, however, require people to speak in simple terms, with appropriate pauses, and use specific word orders. There are many times when she will say "I'm sorry, I don't know the answer to that question." More than likely, she doesn't recognize a word order or misunderstood the question.
Some Alexa Skills connect to smart devices, bringing voice control to a smart home from smart lights to locks, smart thermostats to televisions and more. Alexa becomes a home's second in command: users tell Alexa to tell other devices what to do. There are Alexa Skills for almost any kind of smart home device. These Alexa Smart Home articles can get users started immediately, quick start guides for using Alexa: 8 Alexa skills for your professionally installed and monitored security systems, 5 Alexa skills for security you install yourself, but have professionally monitored, and Alexa Skills that help lock down the security of your smart home.