Because Amazon opened up the development of Alexa Skills to anyone with the free Alexa Skills Kit (ASK) in 2015, anyone can create an Alexa Skill. As Alexa uses Natural Language Programing (NLP), those looking to build a skill don't need to worry about complex speech recognition. The ASK tools also makes it easier for novices to work with sophisticated NLP ideas.
You'll notice in the lists below that many Alexa skills are called by using trigger words like open, start, play and ask. While select skills require you to use specific terms, others consider them to be interchangeable and will work with some or all of these phrases. Over time you'll begin launching your favorite skills by the words you feel most comfortable using. Initially, though, it can be fun to play around with each.
In the Alexa app, this is achieved by selecting the main menu button (found in the upper left-hand corner of the screen) and choosing the Skills option. From here you can browse Alexa skills by category or other criteria such as those favored the most by its large user base. You can also search for skills by keyword or name through this same interface.
Alexa Skills themselves are quite helpful. However, even with an updated Skills section in the Alexa app and the ability to add skills using only your voice, discovering new and useful skills is a less than desirable experience. So much so that Amazon actually created a skill called Skill Finder which, you guessed it, helps you discover new skills. Launch it by saying, "Alexa, open Skill Finder" or "Alexa, tell Skill Finder to give me the skill of the day."
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.