The full line of Alexa-enabled products: From left, the Amazon Tap, Fire TV, Echo and Echo Dot. (Courtesy of Amazon)

Amazon on Thursday expanded its line of devices that work with its omnipotent Alexa voice assistant by adding two new portable devices powered by the know-it-all software.

The first product is the $90 Echo Dot, which is essentially the top part of the $180 Amazon Alexa-powered Echo speaker. The Dot is a small disc that plugs into the wall and has all the software features of the larger device, but doesn't have the original Echo's large speaker for listening to music. Instead, it's designed to plug into existing speakers. It's basically the option for those who already have a home sound system they like but want to turn their normal "dumb" speaker into a smart, Internet-connected one.

The Dot does have a small built-in speaker for answering commands or playing alarms. But for really listening to music, users will want to plug it into a larger speaker.

The Dot is available only through Amazon's Alexa Voice Shopping service, which lets you order things through the voice assistant. To do that you must be a member of Amazon Prime and have a compatible device: namely, the Amazon Echo. Amazon hasn't offered any information on when the Dot might become available to a broader audience, but it says on its website that "when we sell out of Echo Dot devices, they will no longer be available." The company declined to offer more information on future availability.

It's much easier to buy the Amazon Tap, however, which is a $130 Bluetooth speaker up for pre-order now and set to ship at the end of March. Like the Echo and the Dot, it also uses Alexa's voice-controlled features when connected to a WiFi network. Unlike other Alexa-based products, the Tap is portable and battery-powered, promising nine hours of use between charging. It also requires you to actually hit the button on the top of the speaker to speak to Alexa, so there's no need to yell your requests at her.

The Tap is designed more as an on-the-go item than a home assistant, and competes directly with portable speakers like the Logitech UE Boom than with its fellow Alexa-powered products.

The rollout of the Dot and Tap fits into a larger push from Amazon to insinuate itself into more parts of your life. Its Internet-connected Dash ordering buttons, for example, let you order things from its site by attaching a button to the side of your dishwasher, washing machine or wall. Some appliances even have these ordering features built in, so your water pitcher can order more filters more or less on its own.

In a separate Thursday announcement, smart thermostat maker Nest said that it will support Alexa commands, making it possible to speak to your Echo or Fire TV to change your home's temperature, or tell Alexa you're going out and have her adjust the climate accordingly. This is a fairly big announcement, given that Nest -- which, like Google, is owned by Alphabet-- is a major Amazon competitor for long-term control of the smart home trend.

But in the short term, the ability to have an Alexa presence in multiple rooms in your home -- or clipped on to your backpack -- means you'll never have to be far from the retail giant and never have to work to hard to buy something from it.

If, you know, that's what you want.

(Amazon chief executive Jeffrey Bezos owns The Washington Post.)